ACS Publications. Most Trusted. Most Cited. Most Read
Quick View

OR SEARCH CITATIONS

My Activity
Publications
CONTENT TYPES

Figure 1Loading Img
Download Hi-Res ImageDownload to MS-PowerPointCite This:Langmuir 2018, 34, 23, 6820-6826
RETURN TO ISSUEPREVArticleNEXT

A Versatile AuNP Synthetic Platform for Decoupled Control of Size and Surface Composition

Cite this: Langmuir 2018, 34, 23, 6820–6826
Publication Date (Web):May 16, 2018
https://doi.org/10.1021/acs.langmuir.8b00353

Copyright © 2018 American Chemical Society. This publication is licensed under these Terms of Use.

Request reuse permissions
  • Open Access

Article Views

4010

Altmetric

-

Citations

24
LEARN ABOUT THESE METRICS
PDF (4 MB)
Get e-Alerts
Supporting Info (1)»
SUBJECTS:

Abstract

High Resolution Image
Download MS PowerPoint Slide

While a plethora of protocols exist for the synthesis of sub-10-nm gold nanoparticles (AuNPs), independent control over the size and surface composition remains restricted. This poses a particular challenge for systematic studies of AuNP structure–function relationships and the optimization of crucial design parameters. To this end, we report on a modular two-step approach based on the synthesis of AuNPs in oleylamine (OAm) followed by subsequent functionalization with thiol ligands and mixtures thereof. The synthesis of OAm-capped AuNPs enables fine-tuning of the core size in the range of 2–7 nm by varying the reaction temperature. The subsequent thiol-for-OAm ligand exchange allows a reliable generation of thiol-capped AuNPs with target surface functionality. The compatibility of this approach with a vast library of thiol ligands provides detailed control of the mixed ligand composition and solubility in a wide range of solvents ranging from water to hexane. This decoupled control over the AuNP core and ligand shell provides a powerful toolbox for the methodical screening of optimal design parameters and facile preparation of AuNPs with target properties.

Introduction

ARTICLE SECTIONS
Jump To
Among all of the nanomaterial systems, gold nanoparticles (AuNPs) are one of the most widely studied material platforms. With distinct chemical and physical properties, AuNPs have become vital components in various optical, (1,2) catalytic, (3−5) chemical, and biomedical (6−9) applications. Sub-10-nm AuNPs are of particular interest for a number of reasons. Functionalization with a densely packed self-assembled monolayer of thiol ligands offers reliable core protection and long-term colloidal stability, provided by the strong interaction between gold and sulfur. (10,11) The broad library of available capping agents and its size range makes these types of AuNPs promising candidates as biomedical agents and as building blocks in constructing nanostructures with higher orders. (12−15)
The chemical nature of the stabilizing ligand shell structure is decisive for many NP properties, including solubility, chemical reactivity, and binding affinity. (16−20) It has been reported that the interrelationship between NP size and surface properties is key for controlling cellular uptake (21) and protein adsorption. (22,23) This demand poses challenges for existing preparation protocols as most are parameter-sensitive wet-chemistry syntheses. For example, although uniformly distributed thiol-protected AuNPs can be synthesized, both the classical one-step Brust–Schiffrin method (24) and the one-phase version (25) suffer from a divergence of the NP core diameter when varying the composition of the ligand shell, making comparability and systematic studies difficult. (26)
Exchange of the capping agent offers a viable route to decoupling gold core preparation from ligand shell functionalization. (27,28) In the so-called place-exchange reaction, an excess of target ligands is introduced to replace the existing protecting shell. (29) The kinetics and evolution of the ligand shell morphology in thiol-for-thiol exchange reactions were recently studied in great detail. (30) An alternative is the synthesis of AuNPs with a more labile intermediate capping agent to facilitate the exchange. The use of AuNP protectants such as citrate, (31) phosphine, (32,33) 4-(N,N-dimethylamino)pyridine (DMAP), (34,35) dioctylamine (DOA), (36) and tetraoctylammonium bromide (TOAB) (37) allows us to separate the synthesis of the AuNP core and the formation of a tailored ligand shell via a thiol-for-agent ligand-exchange procedure. (37)
While each of the routes described above has been successfully implemented in certain protocols, their general applicability is limited by drawbacks such as (i) the available AuNP size range and size tunability, (ii) the uniformity in size and shape of the AuNP core, (iii) the stability and exchangeability of the intermediate capping agent, (iv) the yield and scalability of the reaction, and (v) the practicality of the procedure. Reliable thiol-for-thiol exchange is time-consuming, with most protocols requiring daylong procedures. (30) Because of the strong association between the capping agent and the gold core, it is generally challenging to achieve complete and homogeneous substitution. Typically, replacement thiols are introduced in large excess, which raises concerns over partial etching of the AuNP core. (38,39) For citrate-based AuNPs, the available size range is typically 10–150 nm, (40) though some protocols exists to tune the mean size below this range. (41) In contrast, phosphine-based protocols are limited to <2 nm. For DMAP-based, DOA-based, and TOAB-based AuNPs, the available uniformity and tunability of the AuNP core are somewhat restricted. (36,42,43) Moreover, it remains a challenge to achieve a satisfiable yield and compatibility with large-scale synthesis when the intermediate AuNP complex is unstable. (33,44)
The use of oleylamine (OAm) in AuNP synthesis has attracted considerable interest due to its ability to play multiple roles as surfactant, solvent, and reducing agent. (45) OAm alone is able to reduce the gold precusor and stabilize >8 nm AuNPs at elevated temperature (>80 °C) in small-scale syntheses. (46−49) Recently, the introduction of additional reducing agents enabled the facile production of smaller AuNPs with a narrow size distribution and size tunability near room temperature. (50,51) The potential of further surface functionalization by ligand exchange was recently validated for alkylthiol, (52) biphenylthiol, (53) azothiol, (54) and charged thiol mixtures. (55)
Based on OAm as intermediated capping agent, we herein report on a two-step protocol for independent control over AuNP core and ligand shells. We study the applicability of this approach to produce thiol-capped AuNPs via thiol-for-OAm ligand replacement and establish a successful procedure to tune the core size as well as the capping-layer composition within a broad library of thiol ligands and mixtures thereof. The resulting AuNPs exhibit solubilities ranging from hexane to water and are ideally suited for systematic studies of AuNP structure–function relationships as well as AuNP engineering of crucial design parameters.

Experimental Section

ARTICLE SECTIONS
Jump To

Synthesis of OAm-AuNPs

The chemicals were purchased from Sigma-Aldrich (U.K.) and used without further purification unless otherwise stated. A generic OAm-AuNP synthesis started with the preparation of the precursor at room temperature (RT, 20 °C) by dissolving 0.5 mmol of hydrogen tetrachloroaurate (III) hydrate (HAuCl4·3H2O, 95%) in a 40 mL solvent mixture of OAm (C18 content: 80%–90%) and n-octane (97%) (1:1 v/v). The solution was sonicated under a flow of argon (Ar) for 10 min before stirring at a designated reaction temperature. For the precise control of the reaction temperature, a 100 mL jacketed flask was used in the synthesis with a temperature-controlled circulating bath (Grant Instruments, GR150-R2). The reducing solution was prepared by dissolving 0.5 mmol of t-butylamine-borane complex (tBAB, 97%) in 1 mL of OAm and 1 mL of octane before the injection into the precursor solution under vigorous stirring. The mixture was left reacting in an Ar atmosphere at the specified reaction temperature for 2 h before 30 mL of acetone was added to quench the reaction. Various batches of OAm-AuNPs were prepared in octane to study the effect of the reaction temperature in the range of 1–50 °C. The scalability of this method was studied at 15 °C, when 0.25 and 1.0 mmol of HAuCl4 were used, respectively. The AuNPs were collected by centrifugation at 5000g for 10 min and then redispersed in dichloromethane (DCM). The obtained samples were dried in a vacuum desiccator after repeated washing in ethanol.

Thiol-for-OAm Ligand Exchange for AuNPs with a Homoligand Shell

The general procedure of the ligand-exchange process started by dissolving 0.2 mmol of the designated thiol ligand mixture in 10 mL of DCM by vigorous stirring at RT for 10 min. Subsequently, 30 mg of the OAm-capped AuNPs in 5 mL of DCM solution was injected, and the solution was allowed to react at RT for 6 h. To terminate the ligand-exchange procedure of organic-soluble AuNPs, the solution was first evaporated in a rotary evaporator before washing with methanol (MeOH) or acetone three times to remove the excess free ligands in solution. In the case of targeting water-soluble AuNPs, MeOH or acetone was directly added to terminate the reaction. The functionalized AuNPs were collected by repetitive centrifugation at 5000g for 10 min before further drying in a vacuum desiccator. Various batches using the following thiol ligands were prepared with the same protocol: 1-hexanethiol (HT, 97%), 1-octanethiol (OT, 98%), 11-mercapto-1-undecanol (MUO, 97%), 2-phenylethanethiol (PET, 98%), MDDCBO (synthesis adapted from a reported protocol, (42) see SI), MNT (synthesis adapted from protocol, (56) see SI), 11-mercaptoundecanoic acid (MUA, 95%), and 11-mercapto-1-undecanesulfonate (MUS) (synthesized as reported, (57) see SI). For a more detailed summary of the results, see Table 1.
Table 1. Thiol Ligands Used for Homoligand AuNPs
To compare the ligand density of thiol-protected AuNPs prepared by the two-step OAm ligand-exchange method via a classical one-step synthesis, OT-capped AuNPs were prepared following the single-phase protocol developed by Stucky and co-workers. (25) In detail, 0.5 mmol of chloro(triphenylphosphine)gold(I) (95%) was mixed with 2 mmol of OT at 80 °C followed by subsequent reduction with 5 mmol of tBAB at the same temperature for 1 h. The solution was cooled to 40 °C before the addition of 30 mL of MeOH. The AuNPs were collected after washing three times in acetone and subsequent vacuum drying.

Thiol-for-OAm Ligand Exchange for AuNPs with a Mixed-Ligand Shell

Similar to the functionalization of a homoligand shell, mixed-ligand AuNPs were prepared by mixing 0.2 mmol of the thiol ligand mixture at a given feed ratio with 30 mg of the OAm-capped AuNPs in DCM. Functionalized AuNPs with the following ligand mixtures (molar feed ratio) were used: MUO-PET (50–50%), MNT-HT (60–40%), MDDCBO-HT (60–40%), and MUS-OT (60–40%). For MUS-OT composition variation, the following prescriptions were introduced: 80–20, 60–40, 40–60, and 20–80%.

Characterization

A high-resolution 200 keV transmission electron microscope (TEM) system (JEOL, JEM-2010) was used for size imaging. UV–visible (UV–vis) absorption was measured with a fiber-based setup that combined a stabilized tungsten–halogen light source (Thorlabs, SLS201/M, a cuvette holder (Quantum Northwest, qpod 2e) and a high-sensitivity spectrometer (Ocean Optics, QE-Pro). Thermogravimetric analysis (TGA) was studied with a thermogravimetric analyzer (TA Instruments, TGA 550) at a ramp rate of 20 °C/min from RT to 550 °C. Proton nuclear magnetic resonance (1H NMR) results were obtained at 400 MHz (Bruker, Avance III). NMR analysis was carried out in two steps. First, the effectiveness of AuNP washing was verified by line broadening of the surface-bound thiol ligands. Subsequently, ligand desorption was induced by the addition of iodine (I2); see the Supporting Information.

Results and Discussion

ARTICLE SECTIONS
Jump To
The synthesis platform based on AuNP synthesis with OAm as an intermediate capping agent and subsequent thiol-for-OAm ligand exchange is illustrated in Figure 1. While the reaction temperature is used as sole parameter to tune the AuNP core size in the initial synthesis, subsequent ligand exchange involving thiols (in minimum excess) allows us to produce thiol-capped AuNPs with ionic, amphiphathic, and hydrophobic ligand functionalization as well as mixtures thereof.

Figure 1

Figure 1. Schematic of two-step gold nanoparticle (AuNP) preparation consisting of AuNP synthesis with oleylamine (OAm) and subsequent functionalization via thiol-for-OAm ligand exchange.

High Resolution Image
Download MS PowerPoint Slide

Fine Tuning of the OAm-AuNP Core Size with Temperature

The synthesis of OAm-capped AuNPs was revisited using the burst nucleation method based on the reduction of HAuCl4 by tBAB. (50) A representative image of AuNPs stemming from synthesis at different reaction temperatures is shown in Figure 2a. The resulting size distribution as a function of reaction temperature is summarized in Figure 2b with characteristic histograms for each temperature in the Supporting Information (Figure S1). A clear effect of the reaction temperature variation on the resulting AuNP size can be observed. For example, at a reaction temperature of 1 °C, AuNPs with an average size of 6.3 ± 0.7 nm were obtained, which reduced to 5.0 ± 0.6 nm for 10 °C, 4.0 ± 0.6 nm for 20 °C, 3.0 ± 0.5 nm for 30 °C, and 2.2 ± 0.4 nm for 40 °C. An increase in the reaction temperature to 50 °C did not lead to a further reduction of the average diameter (2.2 ± 0.4 nm). Thus, by controlling only a single experimental parameter, the reaction temperature, the average size of the AuNPs was systematically tuned in the range of 2–7 nm. These results are in line with reported values for OAm-based synthesis in octane (26) and show a trend similar to that of the OAm-based synthesis in tetralin. (50) Moreover, this approach yielded excellent scalability as evidenced by the consistent results when varying the batch size by a factor of 4. At 15 °C, the size distributions for 0.25, 0.5, and 1.0 mmol HAuCl4 batch sizes were determined to be 4.6 ± 0.5, 4.6 ± 0.6, and 4.7 ± 0.6 nm, respectively (Supporting Information, Figure S2). This simple tunability over such a broad size range makes the OAm-based AuNP synthesis an ideal base for the subsequent functionalization via thiol-for-OAm replacement.

Figure 2

Figure 2. Oleylamine-based synthesis of gold nanoparticles. (a) Representative TEM images for different reaction temperatures. (b) Average size and standard deviation of the nanoparticle populations as a function of reaction temperature.

High Resolution Image
Download MS PowerPoint Slide

Ligand Packing Density

While OAm-based synthesis was previously introduced as a reliable procedure for AuNP preparation, the primary aim of this work was to use this protocol as a base for subsequent functionalization with a broad range of target thiol ligands and mixtures thereof. In order to compare the ligand shell of 1-octanethiol (OT)-capped AuNPs after thiol-for-OAm exchange (OAm-OT AuNP) with those obtained directly by a one-phase method (OT AuNP), batches were prepared for each method and dried thoroughly by rotary evaporation and subsequently overnight in a vacuum desiccator. The TGA results of those samples are presented in Figure S8. The weight loss observed in the range below 600 °C can be exclusively related to the decomposition of the organic ligand shell as most of the organic component is converted to H2O or CO2 in air. This conversion predominantly was observed at around 200 °C for OT ligands. From TEM images, the average sizes of OAm-OT and OT AuNPs were analyzed to be 4.9 ± 0.4 and 4.4 ± 0.4 nm in diameter, respectively. Combining the weight loss determined by TGA and the average size from TEM analysis, the ligand density of OAm-OT AuNPs and OT AuNPs was determined to be 4.5 and 4.7 ligands/nm2 using a simplified spherical model (58) (Table S1). The similarity in the ligand packing between the two synthesis routes suggests that the OAm method is an ideal alternative to the established one-step, one-phase method with distinct advantages. While the reaction temperature is an important parameter in the one-phase method, size control over the full reported range typically requires further adjustment of the reaction solvent mixture. (25) More importantly, the type of thiol ligand plays an important role in the observed size distribution of the AuNP core, making it particularly difficult to independently vary both parameters in systematic studies. (32)

Variation of Thiol Capping and Resulting Solubility of AuNPs

Various thiol-capped AuNPs from an extensive library of DCM-soluble ligands were successfully prepared via the presented thiol-for-OAm ligand exchange approach. An overview of the studied ligands and the resulting AuNP solubility after functionalization is shown in Table 1. UV–vis absorption spectroscopy was used to evaluate the AuNP solvation by tracking their respective plasmon resonance peak (Figure S9). The simple but versatile ligand-exchange step enabled the functionalization of thiol-capped AuNPs that could be dissolved in solvents ranging from nonpolar (hexane, toluene, and chloroform) to polar aprotic (DCM) and polar protic solvents (H2O, MeOH, and EtOH). Furthermore, the complete thiol replacement was also evidenced by the disappearance of the OAm characteristic footprint from 1H NMR, as presented in Figure 3. An overview of the obtained yield for both AuNP syntheses in OAm (step 1) and thiol-for-OAm AuNP functionalization (step 2) is shown in the Supporting Information (Table S2). While a reaction yield of 94.9% was recovered for step 1, we obtained yields of 91.6 and 87.8% for subsequent functionalization with MUA and MUO, respectively.

Figure 3

Figure 3. Thiol-for-OAm ligand exchange for homoligand AuNPs. NMR and TGA results for AuNPs before and after thiol-for-OAm ligand exchange using MUS, OT, and MUO, respectively. The 1H NMR spectra of various AuNPs were obtained after purification and subsequent I2-induced ligand desorption.

High Resolution Image
Download MS PowerPoint Slide
AuNPs with various binary mixtures of thiol ligands were also studied by introducing a prescribed feed composition for OAm-AuNPs with a size distribution of 4.9 ± 0.4 nm during the thiol-for-OAm ligand exchange. The UV–vis results of different mixtures (Figure S11) indicate the solubility of MUS-OT AuNPs in H2O, MUO-PET AuNPs in MeOH, MNT-HT AuNPs in chloroform, and MDDCBO-HT AuNPs in the liquid crystal (LC) 4-cyano-4′-pentylbiphenyl (5CB). Most distinct is the effect of a binary ligand mixture on solvation for a combination of MDDCBO and HT. While the homoligand-protected AuNPs with MDDCBO (or HT) showed very limited solubility in 5CB, the binary ligand mixture of MDDCBO and HT greatly improved solvation. This can be explained by the introduction of the short ligand as a spacing agent. (42)

Variation of Ligand Shell Composition for Binary Mixtures of MUS and OT

In order to establish a detailed relationship between the feed ratio of the binary ligand mixture in the thiol-for-OAm exchange step and the resulting ligand composition on the surface of the AuNPs, batches were prepared from six different molecular ratios of MUS and OT. The same OAm-protected AuNPs were used as based material throughout this study, with a size distribution of 3.6 ± 0.5 nm in diameter. In detail, the washed and dried AuNPs after ligand exchange were dissolved in a mixture of D2O and MeOD (batches with MUS) and CDCl3 (the batch with OT only) for the purpose of AuNP (and I2) solvation. The 1H NMR spectra of these solutions maintained only peaks from the solvents or impurities (Figures S12–S17), which suggests that a vast majority of the thiol ligands were attached to the AuNP surface. (59) The addition of I2 in excess gave rise to the distinct and characteristic peaks by the desorption of the thiols from the AuNP surface. By comparing the integration data of peaks contributed by MUS and OT individually, the yield ratio was determined and compared with the original feed ratio, as presented in Figure 4. (57) Interestingly, the resulting surface composition scaled accurately and reproducibly with the feed ratio variation, demonstrating that the ligand composition can be precisely controlled with the herein-presented approach.

Figure 4

Figure 4. Variation of ligand composition for mixed ligand MUS-OT AuNPs through the feed ratio. (a) Chemical shift profile after purification and subsequent I2-induced ligand desorption and (b) the calculated ligand yield ratio with respect to the ligand feed ratio.

High Resolution Image
Download MS PowerPoint Slide
These results are in stark contrast to thiol-for-thiol place exchange reactions, where the difference in thiol affinity for the gold surface poses a challenge for the consistent variation and tunability of the effective binary ligand composition on the AuNPs. (60,61) In the present approach, the dominating competition for surface adsorption is between thiol and OAm rather than thiol and thiol. The composition variation was further supported by the TGA results shown in the Supporting Information (Figure S18). On the basis of the ligand shell molar ratio of MUS and OT obtained by NMR analysis, the partial packing density for each ligand component was calculated for the different MUS-OT batches, as shown in Table S3.
We note that for reliable and reproducible functionalization with a consistent relationship between the ligand feed in solution and ligand yield on the AuNPs, the presented route relies on the solubility of the respective target thiols in a common solvent with the OAm-protected AuNPs, here DCM. A vast library of thiol ligands are either hydrophobic or amphipathic and thus compatible with the approach. Indeed, most of the commonly used thiol ligands exhibit a hydrophobic alkyl backbone with a functional (and often polar) end group. In contrast, hydrophilic thiols with poor solubility in DCM require functionalization via a two-phase process with H2O, which resulted in less precise control over the ligand composition. Additionally, the above shown tuning of the ligand shell composition by the feed ratio relies on a nonspecific coadsorption of both thiol ligands in a binary mixture. Recent work by Klajn and co-workers elucidated the effect of electrostatic interactions between different ligand types on the final composition of the ligand shell. (55) For a mixture of a positively charged viologen-based ligand and a zwitterionic sulfobetaine ligand, a variation of the ligand feed ratio by a factor of 5000 changed the effective ligand composition on the nanoparticles by only a factor of 3. In more general terms, we anticipate our approach to be a versatile nanoparticle platform for the study of both size and ligand composition on the resulting ligand shell morphology. (62)

Conclusions

ARTICLE SECTIONS
Jump To
The presented synthesis platform for AuNP synthesis enabled the decoupling of core size refinement and ligand shell variation in thiol-capped AuNPs. Following a modified synthesis with OAm as an intermediate protecting capping agent, the core size was tuned in the range of 2–7 nm by varying the reaction temperature. Subsequently, the functionalization of the OAm-AuNPs with a wide choice of thiol ligands and binary mixtures thereof was achieved, resulting in tunable solubility ranging from H2O and alcohols to apolar organic solvents and LCs. Moreover, the thiol-for-OAm ligand exchange method proved to be as efficient as the conventional one-step method in preparing AuNPs with dense ligand packing. For MUS-OT-protected AuNPs, a consistent relationship was established between the thiol ligand mixture in the feed solution and the resulting composition on the AuNP, demonstrating precise control over the surface properties. We regard this synthesis platform as a valuable tool for fabricating thiol-protected AuNPs with rational design optimization for target applications.

Supporting Information

ARTICLE SECTIONS
Jump To

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.langmuir.8b00353.

  • TEM histograms of synthesized NPs; further experimental details; and NMR, TGA, MS, and UV–vis data (PDF)

Terms & Conditions

Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.

Author Information

ARTICLE SECTIONS
Jump To

Acknowledgments

ARTICLE SECTIONS
Jump To

This project received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 633635 (DIACHEMO). Y.Y. acknowledges University College London for the Overseas Research Scholarship and the Graduate Research Scholarship. S.G. is thankful for support by a start-up fund from the Department of Chemical Engineering at University College London. The authors are grateful to Dr. Paulo Jacob Silva and Prof. Francesco Stellacci (EPFL) for providing the MUS ligand and Dr. Jakub W. Trzcinski for valuable feedback on the manuscript.

References

ARTICLE SECTIONS
Jump To

This article references 62 other publications.

  1. 1
    Barnes, W. L.; Dereux, A.; Ebbesen, T. W. Surface Plasmon Subwavelength Optics. Nature 2003, 424, 824– 830,  DOI: 10.1038/nature01937
    Google Scholar
    1
    Surface plasmon subwavelength optics
    Barnes, William L.; Dereux, Alain; Ebbesen, Thomas W.
    Nature (London, United Kingdom) (2003), 424 (6950), 824-830CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)
    A review. Surface plasmons are waves that propagate along the surface of a conductor. By altering the structure of a metal's surface, the properties of surface plasmons - in particular their interaction with light - can be tailored, which offers the potential for developing new types of photonic device. This could lead to miniaturized photonic circuits with length scales that are much smaller than those currently achieved. Surface plasmons are being explored for their potential in subwavelength optics, data storage, light generation, microscopy and bio-photonics.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXmt1ant7g%253D&md5=f34c9c0ea2de46f7b70d9b8aa552a459
  2. 2
    Tian, Y.; Tatsuma, T. Mechanisms and Applications of Plasmon-Induced Charge Separation at TiO2 Films Loaded with Gold Nanoparticles. J. Am. Chem. Soc. 2005, 127, 7632– 7637,  DOI: 10.1021/ja042192u
    Google Scholar
    2
    Mechanisms and Applications of Plasmon-Induced Charge Separation at TiO2 Films Loaded with Gold Nanoparticles
    Tian, Yang; Tatsuma, Tetsu
    Journal of the American Chemical Society (2005), 127 (20), 7632-7637CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    Plasmon-induced photoelectrochem. in the visible region was studied for Au nanoparticle-nanoporous TiO2 composites (Au-TiO2) prepd. by photocatalytic deposition of Au in a porous TiO2 film. Photo-action spectra for open-circuit potential and short-circuit current agreed with the absorption spectrum of Au nanoparticles in the TiO2 film. The Au nanoparticles are photoexcited due to plasmon resonance and charge sepn. is accomplished by the transfer of photoexcited electrons from the Au particle to the TiO2 conduction band with the simultaneous transfer of compensating electrons from a donor in the soln. to the Au particles. In addn. to its low cost and ease of prepn., a photovoltaic cell with the optimized electron mediator, Fe2+/3+, exhibits an optimum incident photon to current conversion efficiency (IPCE) of 26%. The Au-TiO2 can photo-catalytically oxidize EtOH and MeOH at the expense of O redn. under visible light, it is potentially applicable to a new class of photocatalysts and photovoltaic fuel cells.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjslKqtrw%253D&md5=77c3140900eca9cdbae5bc11ad521ccc
  3. 3
    Haruta, M.; Yamada, N.; Kobayashi, T.; Iijima, S. Gold Catalysts Prepared by Coprecipitation for Low-Temperature Oxidation of Hydrogen and of Carbon Monoxide. J. Catal. 1989, 115, 301– 309,  DOI: 10.1016/0021-9517(89)90034-1
    Google Scholar
    3
    Gold catalysts prepared by coprecipitation for low-temperature oxidation of hydrogen and of carbon monoxide
    Haruta, M.; Yamada, N.; Kobayashi, T.; Iijima, S.
    Journal of Catalysis (1989), 115 (2), 301-9CODEN: JCTLA5; ISSN:0021-9517.
    Novel Au catalysts were prepd. by copptn. from an aq. soln. of HAuCl4 and the nitrates of various transition metals. Calcination of the coppts. in air at 400° produced ultrafine Au particles <10 nm which were uniformly dispersed on the transition metal oxides. Among them, Au/α-Fe2O3, Au/Co3O4, and Au/NiO were highly active for H2 and CO oxidn., showing markedly enhanced catalytic activities due to the combined effect of Au and the transition metal oxides. For the oxidn. of CO they were active even at a temp. as low as -70°.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1MXhtVamsbY%253D&md5=e5251756c7ba5548ab855a97d979cce4
  4. 4
    Corma, A.; Garcia, H. Supported Gold Nanoparticles as Catalysts for Organic Reactions. Chem. Soc. Rev. 2008, 37, 2096– 2126,  DOI: 10.1039/b707314n
    Google Scholar
    4
    Supported gold nanoparticles as catalysts for organic reactions
    Corma, Avelino; Garcia, Hermenegildo
    Chemical Society Reviews (2008), 37 (9), 2096-2126CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
    A review. This crit. review is intended to attract the interest of org. chemists and researchers on green and sustainable chem. on the catalytic activity of supported gold nanoparticles in org. transformations. In the general part of this crit. review, emphasis is given to the different procedures to form supported gold nanoparticles and to the importance of the support cooperating in the catalysis. Also the convergence of homogeneous and heterogeneous catalysis in the study of gold nanoparticles has been discussed. The core part of this review is constituted by sections in which the reactions catalyzed by supported gold nanoparticles are described. Special emphasis is made on the unique ability of gold catalysts to promote addns. to multiple C-C bonds, benzannulations, and alc. oxidn. by oxygen.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtVOitbzN&md5=0ced6d30cce14be1fc0f5b295bc610fc
  5. 5
    Wang, C.; Yin, H.; Dai, S.; Sun, S. A General Approach to Noble Metal-Metal Oxide Dumbbell Nanoparticles and Their Catalytic Application for CO Oxidation. Chem. Mater. 2010, 22, 3277– 3282,  DOI: 10.1021/cm100603r
    Google Scholar
    5
    A General Approach to Noble Metal-Metal Oxide Dumbbell Nanoparticles and Their Catalytic Application for CO Oxidation
    Wang, Chao; Yin, Hongfeng; Dai, Sheng; Sun, Shouheng
    Chemistry of Materials (2010), 22 (10), 3277-3282CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)
    Heterogeneous, dumbbell-like nanoparticles represent an important type of composite nano-material which attracts growing interest. A general approach to noble metal/metal oxide dumbbell nanoparticles based on seed-mediated growth is reported. Metal oxides are grown over pre-synthesized noble metal seeds by thermal decompn. of metal carbonyl followed by oxidn. in air. As-synthesized dumbbell nanoparticles have intrinsic epitaxial links between the metal and oxide, providing enhanced hetero-junction interactions. The properties of one component are readily modified by the other in these nanoparticles, as demonstrated by the enhanced catalytic activity toward CO oxidn. of such dumbbell nanoparticles vs. their counterparts synthesized by conversional methods. Thus, the hetero-junction effects provided in such nano-structures offer another degree of freedom to tailor material properties. The developed synthetic strategy could also be generalized to other systems and therefore represent a general approach to heterogeneous nano-materials for functional applications.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXltFyksbo%253D&md5=1bf31952c58093912137f537cfef9315
  6. 6
    Howes, P. D.; Chandrawati, R.; Stevens, M. M. Colloidal Nanoparticles as Advanced Biological Sensors. Science 2014, 346, 1247390,  DOI: 10.1126/science.1247390
    Google Scholar
    6
    Bionanotechnology. Colloidal nanoparticles as advanced biological sensors
    Howes Philip D; Chandrawati Rona; Stevens Molly M
    Science (New York, N.Y.) (2014), 346 (6205), 1247390 ISSN:.
    Colloidal nanoparticle biosensors have received intense scientific attention and offer promising applications in both research and medicine. We review the state of the art in nanoparticle development, surface chemistry, and biosensing mechanisms, discussing how a range of technologies are contributing toward commercial and clinical translation. Recent examples of success include the ultrasensitive detection of cancer biomarkers in human serum and in vivo sensing of methyl mercury. We identify five key materials challenges, including the development of robust mass-scale nanoparticle synthesis methods, and five broader challenges, including the use of simulations and bioinformatics-driven experimental approaches for predictive modeling of biosensor performance. The resultant generation of nanoparticle biosensors will form the basis of high-performance analytical assays, effective multiplexed intracellular sensors, and sophisticated in vivo probes.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2M7ntVKhug%253D%253D&md5=25ce494a8bbfe4fd7d73818b3267d674
  7. 7
    Dykman, L.; Khlebtsov, N. Gold Nanoparticles in Biomedical Applications: Recent Advances and Perspectives. Chem. Soc. Rev. 2012, 41, 2256– 2282,  DOI: 10.1039/C1CS15166E
    Google Scholar
    7
    Gold nanoparticles in biomedical applications: recent advances and perspectives
    Dykman, Lev; Khlebtsov, Nikolai
    Chemical Society Reviews (2012), 41 (6), 2256-2282CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
    A review. Gold nanoparticles (GNPs) with controlled geometrical, optical, and surface chem. properties are the subject of intensive studies and applications in biol. and medicine. To date, the ever increasing diversity of published examples has included genomics and biosensorics, immunoassays and clin. chem., photothermolysis of cancer cells and tumors, targeted delivery of drugs and antigens, and optical bioimaging of cells and tissues with state-of-the-art nanophotonic detection systems. This crit. review is focused on the application of GNP conjugates to biomedical diagnostics and analytics, photothermal and photodynamic therapies, and delivery of target mols. Distinct from other published reviews, we present a summary of the immunol. properties of GNPs. For each of the above topics, the basic principles, recent advances, and current challenges are discussed (508 refs.).
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XivFWlsbc%253D&md5=b08dfe416c306e5f35a69d0df15bf37d
  8. 8
    Shukla, R.; Bansal, V.; Chaudhary, M.; Basu, A.; Bhonde, R. R.; Sastry, M. Biocompatibility of Gold Nanoparticles and Their Endocytotic Fate inside the Cellular Compartment: a Microscopic Overview. Langmuir 2005, 21, 10644– 10654,  DOI: 10.1021/la0513712
    Google Scholar
    8
    Biocompatibility of Gold Nanoparticles and Their Endocytotic Fate Inside the Cellular Compartment: A Microscopic Overview
    Shukla, Ravi; Bansal, Vipul; Chaudhary, Minakshi; Basu, Atanu; Bhonde, Ramesh R.; Sastry, Murali
    Langmuir (2005), 21 (23), 10644-10654CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
    Macrophages are one of the principal immune effector cells that play essential roles as secretory, phagocytic, and antigen-presenting cells in the immune system. In this study, we address the issue of cytotoxicity and immunogenic effects of gold nanoparticles on RAW264.7 macrophage cells. The cytotoxicity of gold nanoparticles has been correlated with a detailed study of their endocytic uptake using various microscopy tools such as at. force microscopy (AFM), confocal-laser-scanning microscopy (CFLSM), and TEM. Our findings suggest that Au(0) nanoparticles are not cytotoxic, reduce the prodn. of reactive oxygen and nitrite species, and do not elicit secretion of proinflammatory cytokines TNF-α and IL1-β, making them suitable candidates for nanomedicine. AFM measurements suggest that gold nanoparticles are internalized inside the cell via a mechanism involving pinocytosis, while CFLSM and TEM studies indicate their internalization in lysosomal bodies arranged in perinuclear fashion. Our studies thus underline the noncytotoxic, nonimmunogenic, and biocompatible properties of gold nanoparticles with the potential for application in nanoimmunol., nanomedicine, and nanobiotechnol.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtVegt7fM&md5=ea38d76c875da8c93d0e3258f4ae15cf
  9. 9
    Kinnear, C.; Moore, T. L.; Rodriguez-Lorenzo, L.; Rothen-Rutishauser, B.; Petri-Fink, A. Form Follows Function: Nanoparticle Shape and Its Implications for Nanomedicine. Chem. Rev. 2017, 117, 11476– 11521,  DOI: 10.1021/acs.chemrev.7b00194
    Google Scholar
    9
    Form Follows Function: Nanoparticle Shape and Its Implications for Nanomedicine
    Kinnear, Calum; Moore, Thomas L.; Rodriguez-Lorenzo, Laura; Rothen-Rutishauser, Barbara; Petri-Fink, Alke
    Chemical Reviews (Washington, DC, United States) (2017), 117 (17), 11476-11521CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)
    A review. This review is a comprehensive description of the past decade of research into understanding how the geometry and size of nanoparticles affects their interaction with biol. systems: from single cells to whole organisms. Recently, there has been a great deal of effort to use both the shape and size of nanoparticles to target specific cellular uptake mechanisms, biodistribution patterns, and pharmacokinetics. While the successes of spherical lipid-based nanoparticles have heralded marked changes in chemotherapy worldwide, the history of asbestos-induced lung disease casts a long shadow over fibrous materials to date. The impact of particle morphol. is known to be intertwined with many physicochem. parameters, namely size, elasticity, surface chem., and biopersistence. In this review, we first highlight some of the morphologies obsd. in nature, as well as shapes available to us through synthetic strategies. Following this, we discuss attempts to understand the cellular uptake of nanoparticles through various theor. models before comparing this with observations from in vitro and in vivo expts. In addn., we consider the impact of nanoparticle shape at different size regimes on targeting, cytotoxicity, and cellular mechanics.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsVWgt7rF&md5=0c21904caafe4912ff0604dc9a8335df
  10. 10
    Castner, D. G.; Hinds, K.; Grainger, D. W. X-ray Photoelectron Spectroscopy Sulfur 2p Study of Organic Thiol and Disulfide Binding Interactions with Gold Surfaces. Langmuir 1996, 12, 5083– 5086,  DOI: 10.1021/la960465w
    Google Scholar
    10
    X-ray Photoelectron Spectroscopy Sulfur 2p Study of Organic Thiol and Disulfide Binding Interactions with Gold Surfaces
    Castner, David G.; Hinds, Kenneth; Grainger, David W.
    Langmuir (1996), 12 (21), 5083-5086CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
    The presence of 2 S species was detected in XPS studies of thiol and disulfide mols. adsorbed on Au surfaces. These species are assigned to bound thiolate (S2p3/2 binding energy 162 eV) and unbound thiol/disulfide (S2p3/2 binding energy from 163.5 to 164 eV). These assignments are consistent with XPS data obtained from different thiols (C12, C16, C18, and C22 alkane thiols, a fluorinated thiol, and a cyclic siloxanethiol) and different adsorption conditions (solvent type, thiol concn., temp., and rinsing). In particular, the use of a poor solvent for thiol adsorption solns. (e.g., EtOH for long chain alkanethiols) and the lack of a rinsing step both resulted in unbound thiol mols. present at the surface of the bound thiolate monolayer. This has implications for recent studies asserting the presence of multiple binding sites for Au-thiolate species in org. monolayers.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XlvVSgsrg%253D&md5=d5ffa08fd03bf884fa661179edd0de3d
  11. 11
    Bürgi, T. Properties of the Gold-Sulphur Interface: from Self-Assembled Monolayers to Clusters. Nanoscale 2015, 7, 15553– 15567,  DOI: 10.1039/C5NR03497C
    Google Scholar
    11
    Properties of the gold-sulphur interface: from self-assembled monolayers to clusters
    Burgi, Thomas
    Nanoscale (2015), 7 (38), 15553-15567CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)
    The gold-sulfur interface of self-assembled monolayers (SAMs) was extensively studied some time ago. More recently tremendous progress has been made in the prepn. and characterization of thiolate-protected gold clusters. In this feature article we address different properties of the two systems such as their structure, the mobility of the thiolates on the surface and other dynamical aspects, the chirality of the structures and characteristics related to it and their vibrational properties. SAMs and clusters are in the focus of different communities that typically use different exptl. approaches to study the resp. systems. However, it seems that the nature of the Au-S interfaces in the two cases is quite similar. Recent single crystal X-ray structures of thiolate-protected gold clusters reveal staple motifs characterized by gold ad-atoms sandwiched between two sulfur atoms. In any case, more and more studies highlight the dynamic nature of the Au-S interface, both on flat surfaces and in clusters. At temps. slightly above ambient thiolates migrate on the gold surface and on clusters. Evidence for desorption of thiolates at room temp., at least under certain conditions, has been demonstrated for both systems. The adsorbed thiolate can lead to chirality at different lengths scales, which has been shown both on surfaces and for clusters. Chirality can also be transferred from a chiral surface to an adsorbate, as evidenced by vibrational spectroscopy.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsVGju7rE&md5=bc7e3fe58112c953fcb9b52bbb2d4b54
  12. 12
    Giljohann, D. A.; Seferos, D. S.; Daniel, W. L.; Massich, M. D.; Patel, P. C.; Mirkin, C. A. Gold Nanoparticles for Biology and Medicine. Angew. Chem., Int. Ed. 2010, 49, 3280– 3294,  DOI: 10.1002/anie.200904359
    Google Scholar
    12
    Gold Nanoparticles for Biology and Medicine
    Giljohann, David A.; Seferos, Dwight S.; Daniel, Weston L.; Massich, Matthew D.; Patel, Pinal C.; Mirkin, Chad A.
    Angewandte Chemie, International Edition (2010), 49 (19), 3280-3294CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
    A review. Gold colloids have fascinated scientists for over a century and are now heavily utilized in chem., biol., engineering, and medicine. Today these materials can be synthesized reproducibly, modified with seemingly limitless chem. functional groups, and, in certain cases, characterized with at.-level precision. This Review highlights recent advances in the synthesis, bioconjugation, and cellular uses of gold nanoconjugates. There are now many examples of highly sensitive and selective assays based upon gold nanoconjugates. In recent years, focus has turned to therapeutic possibilities for such materials. Structures which behave as gene-regulating agents, drug carriers, imaging agents, and photoresponsive therapeutics have been developed and studied in the context of cells and many debilitating diseases. These structures are not simply chosen as alternatives to mol.-based systems, but rather for their new phys. and chem. properties, which confer substantive advantages in cellular and medical applications.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXlt1GlsbY%253D&md5=0809d2a7d09124a8975d5ea77e679442
  13. 13
    Saha, K.; Agasti, S. S.; Kim, C.; Li, X.; Rotello, V. M. Gold Nanoparticles in Chemical and Biological Sensing. Chem. Rev. 2012, 112, 2739– 2779,  DOI: 10.1021/cr2001178
    Google Scholar
    13
    Gold nanoparticles in chemical and biological sensing
    Saha, Krishnendu; Agasti, Sarit S.; Kim, Chaekyu; Li, Xiaoning; Rotello, Vincent M.
    Chemical Reviews (Washington, DC, United States) (2012), 112 (5), 2739-2779CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)
    A review. Topics include synthesis ans surface functionalization; phys. properties; colorimetric and fluorimetric sensing; elec. al and electrochem. sensing; SERS; gold nanoparticles in quartz crystal microbalance-based sensing; application of gold nanoparticles in bio-barcode assays.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xhs1ehtL0%253D&md5=350c3c2eeab3d98ed42ffe88cf137c14
  14. 14
    Yeh, Y.-C.; Creran, B.; Rotello, V. M. Gold Nanoparticles: Preparation, Properties, and Applications in Bionanotechnology. Nanoscale 2012, 4, 1871– 1880,  DOI: 10.1039/C1NR11188D
    Google Scholar
    14
    Gold nanoparticles: preparation, properties, and applications in bionanotechnology
    Yeh, Yi-Cheun; Creran, Brian; Rotello, Vincent M.
    Nanoscale (2012), 4 (6), 1871-1880CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)
    A review. Gold nanoparticles (AuNPs) are important components for biomedical applications. AuNPs have been widely employed for diagnostics, and have seen increasing use in the area of therapeutics. In this mini-review, we present fabrication strategies for AuNPs and highlight a selection of recent applications of these materials in bionanotechnol.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XjtFyqsL4%253D&md5=324ab15e57fc9535c4180020852b374a
  15. 15
    Le Ouay, B.; Guldin, S.; Luo, Z.; Allegri, S.; Stellacci, F. Freestanding Ultrathin Nanoparticle Membranes Assembled at Transient Liquid-Liquid Interfaces. Adv. Mater. Interfaces 2016, 3, 1600191,  DOI: 10.1002/admi.201600191
    Google Scholar
    There is no corresponding record for this reference.
  16. 16
    DeVries, G. A.; Brunnbauer, M.; Hu, Y.; Jackson, A. M.; Long, B.; Neltner, B. T.; Uzun, O.; Wunsch, B. H.; Stellacci, F. Divalent Metal Nanoparticles. Science 2007, 315, 358– 361,  DOI: 10.1126/science.1133162
    Google Scholar
    16
    Divalent Metal Nanoparticles
    DeVries, Gretchen A.; Brunnbauer, Markus; Hu, Ying; Jackson, Alicia M.; Long, Brenda; Neltner, Brian T.; Uzun, Oktay; Wunsch, Benjamin H.; Stellacci, Francesco
    Science (Washington, DC, United States) (2007), 315 (5810), 358-361CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)
    Nanoparticles can be used as the building blocks for materials such as supracrystals or ionic liqs. However, they lack the ability to bond along specific directions as atoms and mols. do. We report a simple method to place target mols. specifically at two diametrically opposed positions in the mol. coating of metal nanoparticles. The approach is based on the functionalization of the polar singularities that must form when a curved surface is coated with ordered monolayers, such as a phase-sepd. mixt. of ligands. The mols. placed at these polar defects have been used as chem. handles to form nanoparticle chains that in turn can generate self-standing films.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXmt1Kgsg%253D%253D&md5=722ecd96276839ab19cbdccb3a1c2c34
  17. 17
    Kuna, J. J.; Voïtchovsky, K.; Singh, C.; Jiang, H.; Mwenifumbo, S.; Ghorai, P. K.; Stevens, M. M.; Glotzer, S. C.; Stellacci, F. The Effect of Nanometre-Scale Structure on Interfacial Energy. Nat. Mater. 2009, 8, 837– 842,  DOI: 10.1038/nmat2534
    Google Scholar
    17
    The effect of nanometre-scale structure on interfacial energy
    Kuna, Jeffrey J.; Voitchovsky, Kislon; Singh, Chetana; Jiang, Hao; Mwenifumbo, Steve; Ghorai, Pradip K.; Stevens, Molly M.; Glotzer, Sharon C.; Stellacci, Francesco
    Nature Materials (2009), 8 (10), 837-842CODEN: NMAACR; ISSN:1476-1122. (Nature Publishing Group)
    Natural surfaces are often structured with nanometer-scale domains, yet a framework providing a quant. understanding of how nanostructure affects interfacial energy, γSL, is lacking. Conventional continuum thermodn. treats γSL solely as a function of av. compn., ignoring structure. When a surface has domains commensurate in size with solvent mols., γSL is detd. not only by its av. compn. but also by a structural component that causes γSL to deviate from the continuum prediction by a substantial amt., ≤20% in the system. By contrasting surfaces coated with either mol.- ( < 2 nm) or larger-scale domains ( > 5 nm), whereas the latter surfaces have the expected linear dependence of γSL on surface compn., the former show a markedly different nonmonotonic trend. Mol. dynamics simulations show how the organization of the solvent mols. at the interface is controlled by the nanostructured surface, which in turn appreciably modifies γSL.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtFKns7rO&md5=d99bf092f66293176d2f9caa62a08634
  18. 18
    Colangelo, E.; Comenge, J.; Paramelle, D.; Volk, M.; Chen, Q.; Lévy, R. Characterizing Self-Assembled Monolayers on Gold Nanoparticles. Bioconjugate Chem. 2017, 28, 11– 22,  DOI: 10.1021/acs.bioconjchem.6b00587
    Google Scholar
    18
    Characterizing Self-Assembled Monolayers on Gold Nanoparticles
    Colangelo, Elena; Comenge, Joan; Paramelle, David; Volk, Martin; Chen, Qiubo; Levy, Raphael
    Bioconjugate Chemistry (2017), 28 (1), 11-22CODEN: BCCHES; ISSN:1043-1802. (American Chemical Society)
    A review. A key aspect of nanoscience is to control the assembly of complex materials from a "bottom-up" approach. The self-assembly and self-organization of small ligands at the surface of nanoparticles represent a possible starting route for the prepn. of (bio)nanomaterials with precise (bio)phys. and (bio)chem. properties. However, surface characterization and elucidation of the structure-properties relation, essentials to envision such control, remain challenging and are often poorly studied. This Topical Review aims to discuss different levels of surface characterization, giving an overview of the exptl. and computational approaches that were used to provide insights into the self-assembled monolayer with mol. details. The methods and strategies discussed focus on the characterization of self-assembled monolayers at the gold nanoparticle surface, but most of them could also be applied to other types of nanoparticles.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhvVGgsLnO&md5=c9446bb052f314b3720360d65551fe1b
  19. 19
    Bradford, S. M.; Fisher, E. A.; Meli, M.-V. Ligand Shell Composition-Dependent Effects on the Apparent Hydrophobicity and Film Behavior of Gold Nanoparticles at the Air-Water Interface. Langmuir 2016, 32, 9790– 9796,  DOI: 10.1021/acs.langmuir.6b02238
    Google Scholar
    19
    Ligand Shell Composition-Dependent Effects on the Apparent Hydrophobicity and Film Behavior of Gold Nanoparticles at the Air-Water Interface
    Bradford, Stephen M.; Fisher, Elizabeth A.; Meli, M.-Vicki
    Langmuir (2016), 32 (38), 9790-9796CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
    Nanoparticles with well-defined interfacial energy and wetting properties are needed for a broad range of applications involving nanoparticle self-assembly including the formation of superlattices, stability of Pickering emulsions, and for the control of nanoparticle interactions with biol. membranes. Theor., simulated, and recent exptl. studies have found nanometer-scale chem. heterogeneity to have important effects on hydrophobic interactions. Here we report the study of 4 nm gold nanoparticles with compositionally well-defined mixed ligand shells of hydroxyl-(OH) and methyl-(CH3) terminated alkylthiols as Langmuir films. Compns. ranging from 0-25% hydroxyl were examd. and reveal nonmonotonic changes in particle hydrophobicity at the air-water interface. Unlike nanoparticles capped exclusively with a methyl-terminated alkylthiol, extensive particle aggregation is found for ligand shells contg. <2% hydroxyl-terminated chains. This aggregation was lessened upon increasing the quantity of OH-terminated chains. Nanoparticles capped with 25% OH yield films of well-sepd. nanoparticles exhibiting a fluid-phase regime in the surface pressure vs area isotherm. Compression-expansion hysteresis, monolayer collapse, and mean nanoparticle area measurements support the TEM-obsd. changes in film morphol. Such clear changes in the hydrophobicity of nanoparticles based on very small changes in the ligand shell compn. are shown to impact the process of interfacial nanoparticle self-assembly and are an important demonstration of nanoscale wetting with consequences in both materials and biol. applications of nanoparticles that require tunable hydrophobicity.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsVKrtLbP&md5=a3a7ba1ff2c734f15933f7c2164fb2dc
  20. 20
    Edwards, W.; Marro, N.; Turner, G.; Kay, E. R. Continuum Tuning of Nanoparticle Interfacial Properties by Dynamic Covalent Exchange. Chem. Sci. 2018, 9, 125– 133,  DOI: 10.1039/C7SC03666C
    Google Scholar
    20
    Continuum tuning of nanoparticle interfacial properties by dynamic covalent exchange
    Edwards, William; Marro, Nicolas; Turner, Grace; Kay, Euan R.
    Chemical Science (2018), 9 (1), 125-133CODEN: CSHCCN; ISSN:2041-6520. (Royal Society of Chemistry)
    Surface chem. compn. is fundamental to detg. properties on the nanoscale, making precise control over surface chem. crit. to being able to optimize nanomaterials for virtually any application. Surface-engineering independent of the prepn. of the underlying nanomaterial is particularly attractive for efficient, divergent synthetic strategies, and for the potential to create reactive, responsive and smart nanodevices. For monolayer-stabilized nanoparticles, established methods include ligand exchange to replace the ligand shell in its entirety, encapsulation with amphiphilic (macro)mols., noncovalent interactions with surface-bound biomols., or a relatively limited no. of covalent bond forming reactions. Yet, each of these approaches has considerable drawbacks. Here we show that dynamic covalent exchange at the periphery of the nanoparticle-stabilizing monolayer allows surface-bound ligand mol. structure to be substantially modified in mild and reversible processes that are independent of the nanoparticle-mol. interface. Simple stoichiometric variation allows the extent of exchange to be controlled, generating a range of kinetically stable mixed-monolayer compns. across an otherwise identical, self-consistent series of nanoparticles. This approach can be used to modulate nanoparticle properties that are defined by the monolayer compn. We demonstrate switching of nanoparticle solvent compatibility between widely differing solvents - spanning hexane to water - and the ability to tune soly. across the entire continuum between these extremes, all from a single nanoparticle starting point. We also demonstrate that fine control over mixed-monolayer compn. influences the assembly of discrete, colloidally stable nanoparticle clusters. By carefully assessing monolayer compn. in each state, using both in situ and ex situ methods, we are able to correlate the mol.-level details of the nanoparticle-bound monolayer with system-level properties and behavior. These empirically detd. relationships contribute fundamental insights on nanoscale structure-function relationships, which are currently beyond the capabilities of ab initio prediction.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhvVartLrK&md5=ae50291b8d189e5f4e5835cd0f725c54
  21. 21
    Jiang, Y.; Huo, S.; Mizuhara, T.; Das, R.; Lee, Y.-W.; Hou, S.; Moyano, D. F.; Duncan, B.; Liang, X.-J.; Rotello, V. M. The Interplay of Size and Surface Functionality on the Cellular Uptake of Sub-10 nm Gold Nanoparticles. ACS Nano 2015, 9, 9986– 9993,  DOI: 10.1021/acsnano.5b03521
    Google Scholar
    21
    The Interplay of Size and Surface Functionality on the Cellular Uptake of Sub-10 nm Gold Nanoparticles
    Jiang, Ying; Huo, Shuaidong; Mizuhara, Tsukasa; Das, Riddha; Lee, Yi-Wei; Hou, Singyuk; Moyano, Daniel F.; Duncan, Bradley; Liang, Xing-Jie; Rotello, Vincent M.
    ACS Nano (2015), 9 (10), 9986-9993CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)
    Correlation of the surface physicochem. properties of nanoparticles with their interactions with biosystems provides key foundational data for nanomedicine. We report here the systematic synthesis of 2, 4, and 6 nm core gold nanoparticles (AuNP) featuring neutral (zwitterionic), anionic, and cationic headgroups. The cellular internalization of these AuNPs was quantified, providing a parametric evaluation of charge and size effects. Contrasting behavior was obsd. with these systems: with zwitterionic and anionic particles, uptake decreased with increasing AuNP size, whereas with cationic particles, uptake increased with increasing particle size. Through mechanistic studies of the uptake process, we can attribute these opposing trends to a surface-dictated shift in uptake pathways. Zwitterionic NPs are primarily internalized through passive diffusion, while the internalization of cationic and anionic NPs is dominated by multiple endocytic pathways. Our study demonstrates that size and surface charge interact in an interrelated fashion to modulate nanoparticle uptake into cells, providing an engineering tool for designing nanomaterials for specific biol. applications.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs1SisL3J&md5=acb35b2734a4c7ad78d5d26d7a3c22f1
  22. 22
    Hung, A.; Mwenifumbo, S.; Mager, M.; Kuna, J. J.; Stellacci, F.; Yarovsky, I.; Stevens, M. M. Ordering Surfaces on the Nanoscale: Implications for Protein Adsorption. J. Am. Chem. Soc. 2011, 133, 1438– 1450,  DOI: 10.1021/ja108285u
    Google Scholar
    22
    Ordering Surfaces on the Nanoscale: Implications for Protein Adsorption
    Hung, Andrew; Mwenifumbo, Steve; Mager, Morgan; Kuna, Jeffrey J.; Stellacci, Francesco; Yarovsky, Irene; Stevens, Molly M.
    Journal of the American Chemical Society (2011), 133 (5), 1438-1450CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    Monolayer-protected metal nanoparticles (MPMNs) are a newly discovered class of nanoparticles with an ordered, striped domain structure that can be readily manipulated by altering the ratio of the hydrophobic to hydrophilic ligands. This property makes them uniquely suited to systematic studies of the role of nanostructuring on biomol. adsorption, a phenomenon of paramount importance in biomaterials design. In this work, the authors examine the interaction of the simple, globular protein cytochrome C (Cyt C) with MPMN surfaces using exptl. protein assays and computational mol. dynamics simulations. Exptl. assays revealed that adsorption of Cyt C generally increased with increasing surface polar ligand content, indicative of the dominance of hydrophilic interactions in Cyt C-MPMN binding. Protein-surface adsorption enthalpies calcd. from computational simulations employing rigid-backbone coarse-grained Cyt C and MPMN models indicate a monotonic increase in adsorption enthalpy with respect to MPMN surface polarity. These results are in qual. agreement with exptl. results and suggest that Cyt C does not undergo significant structural disruption upon adsorption to MPMN surfaces. Coarse-grained and atomistic simulations furthermore elucidated the important role of lysine in facilitating Cyt C adsorption to MPMN surfaces. The amphipathic character of the lysine side chain enables it to form close contacts with both polar and nonpolar surface ligands simultaneously, rendering it esp. important for interactions with surfaces composed of adjacent nanoscale chem. domains. The importance of these structural characteristics of lysine suggests that proteins may be engineered to specifically interact with nanomaterials by targeted incorporation of unnatural amino acids possessing dual affinity to differing chem. motifs.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXit1Cgtw%253D%253D&md5=92eb8b626057474e80f31812c79a7844
  23. 23
    Huang, R.; Carney, R. P.; Stellacci, F.; Lau, B. L. Protein-Nanoparticle Interactions: the Effects of Surface Compositional and Structural Heterogeneity Are Scale Dependent. Nanoscale 2013, 5, 6928– 6935,  DOI: 10.1039/c3nr02117c
    Google Scholar
    23
    Protein-nanoparticle interactions: the effects of surface compositional and structural heterogeneity are scale dependent
    Huang, Rixiang; Carney, Randy P.; Stellacci, Francesco; Lau, Boris L. T.
    Nanoscale (2013), 5 (15), 6928-6935CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)
    Nanoparticles (NPs) in the biol. environment are exposed to a large variety and concn. of proteins. Proteins are known to adsorb in a corona' like structure on the surface of NPs. In this study, we focus on the effects of surface compositional and structural heterogeneity on protein adsorption by examg. the interaction of self-assembled monolayer coated gold NPs (AuNPs) with two types of proteins: ubiquitin and fibrinogen. This work was designed to systematically investigate the role of surface heterogeneity in nanoparticle-protein interaction. We have chosen the particles as well as the proteins to provide different types (in distribution and length-scale) of heterogeneity. The goal was to unveil the role of heterogeneity and of its length-scale in the particle-protein interaction. Dynamic light scattering and CD spectroscopy were used to reveal different interactions at pH above and below the isoelec. points of the proteins, which is related to the charge heterogeneity on the protein surface. At pH 7.4, there was only a monolayer of proteins adsorbed onto the NPs and the secondary structure of proteins remained intact. At pH 4.0, large aggregates of nanoparticle-protein complexes were formed and the secondary structures of the proteins were significantly disrupted. In terms of interaction thermodn., results from isothermal titrn. calorimetry showed that ubiquitin adsorbed differently onto (1) AuNPs with charged and nonpolar terminals organized into nano-scale structure (66-34 OT), (2) AuNPs with randomly distributed terminals (66-34 brOT), and (3) AuNPs with homogeneously charged terminals (MUS). This difference in adsorption behavior was not obsd. when AuNPs interacted with fibrinogen. The results suggested that the interaction between the proteins and AuNPs was influenced by the surface heterogeneity on the AuNPs, and this influence depends on the scale of surface heterogeneity and the size of the proteins.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtV2ku7zM&md5=7fb21e3661ff44125adede59cdc0dc19
  24. 24
    Brust, M.; Fink, J.; Bethell, D.; Schiffrin, D.; Kiely, C. Synthesis and Reactions of Functionalised Gold Nanoparticles. J. Chem. Soc., Chem. Commun. 1995, 1655– 1656,  DOI: 10.1039/c39950001655
    Google Scholar
    24
    Synthesis and reactions of functionalized gold nanoparticles
    Brust, M.; Fink, J.; Bethell, D.; Schiffrin, D. J.; Kiely, C.
    Journal of the Chemical Society, Chemical Communications (1995), (16), 1655-6CODEN: JCCCAT; ISSN:0022-4936. (Royal Society of Chemistry)
    Stable functionalized Au nanoparticles were prepd. by simultaneous redn. of tetrachloroaurate ions and attachment of p-mercaptophenol to the growing Au nuclei. This gave a material characterized by esterification of the vacant functionality of the bifunctional thiol ligand.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXns1yksrs%253D&md5=5db08af7554698de25477eccbb226449
  25. 25
    Zheng, N.; Fan, J.; Stucky, G. D. One-Step One-Phase Synthesis of Monodisperse Noble-Metallic Nanoparticles and Their Colloidal Crystals. J. Am. Chem. Soc. 2006, 128, 6550– 6551,  DOI: 10.1021/ja0604717
    Google Scholar
    25
    One-Step One-Phase Synthesis of Monodisperse Noble-Metallic Nanoparticles and Their Colloidal Crystals
    Zheng, Nanfeng; Fan, Jie; Stucky, Galen D.
    Journal of the American Chemical Society (2006), 128 (20), 6550-6551CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    A variety of metallic nanoparticles with a narrow size distribution have been synthesized in a facile one-phase method in which amine-borane complexes are applied as reducing agents. It is particularly striking that large colloidal crystals with sizes up to tens of micrometers can directly form from the reaction mixts. without any further treatment. By using the synthetic route described, large-scale syntheses of both mono- and alloyed metallic nanoparticles with a narrow size distribution can be easily achieved.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XjvFyitLw%253D&md5=2cc5c1e96c797aec50ef2a1db97902ee
  26. 26
    Wu, B.-H.; Yang, H.-Y.; Huang, H.-Q.; Chen, G.-X.; Zheng, N.-F. Solvent Effect on the Synthesis of Monodisperse Amine-Capped Au Nanoparticles. Chin. Chem. Lett. 2013, 24, 457– 462,  DOI: 10.1016/j.cclet.2013.03.054
    Google Scholar
    26
    Solvent effect on the synthesis of monodisperse amine-capped Au nanoparticles
    Wu, Bing-Hui; Yang, Hua-Yan; Huang, Hua-Qi; Chen, Guang-Xu; Zheng, Nan-Feng
    Chinese Chemical Letters (2013), 24 (6), 457-462CODEN: CCLEE7; ISSN:1001-8417. (Elsevier B.V.)
    A remarkable solvent effect in a single-phase synthesis of monodisperse amine-capped Au nanoparticles is demonstrated. Oleylamine-capped Au nanoparticles were prepd. via the redn. of HAuCl4 by an amine-borane complex in the presence of oleylamine in an org. solvent. When linear or planar hydrocarbon (e.g., n-hexane, n-octane, 1-octadecylene, benzene, and toluene) was used as the solvent, high-quality monodisperse Au nanoparticles with tunable sizes were obtained. However, Au nanoparticles with poor size dispersity were obtained when tetralin, chloroform or cyclohexane was used as the solvent. The revealed solvent effect allows the controlled synthesis of monodisperse Au nanoparticles with tunable size of 3-10 nm.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXmvV2ltr8%253D&md5=e1fbdc14a226bdaae0c5d6e7c4113429
  27. 27
    Shon, Y.-S.; Choo, H. Organic Reactions of Monolayer-Protected Metal Nanoparticles. C. R. Chim. 2003, 6, 1009– 1018,  DOI: 10.1016/j.crci.2003.08.008
    Google Scholar
    27
    Organic reactions of monolayer-protected metal nanoparticles
    Shon, Young-Seok; Choo, Hosun
    Comptes Rendus Chimie (2003), 6 (8-10), 1009-1018CODEN: CRCOCR; ISSN:1631-0748. (Editions Scientifiques et Medicales Elsevier)
    A review. This paper presents a concise review of various org. reactions of monolayer-protected metal nanoparticles, with an emphasis on their current applications. Org. reactions of monolayer-protected nanoparticles lead to the functionalized nanoparticles, which exhibit interesting properties such as catalytic, electrochem., photoresponsive, chem. sensing, and biocompatible properties.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXoslOgt7w%253D&md5=fd7ee7a2234cca45699fe8dafeee58b1
  28. 28
    Neouze, M.-A.; Schubert, U. Surface Modification and Functionalization of Metal and Metal Oxide Nanoparticles by Organic Ligands. Monatsh. Chem. 2008, 139, 183– 195,  DOI: 10.1007/s00706-007-0775-2
    Google Scholar
    28
    Surface Modification and Functionalization of Metal and Metal Oxide Nanoparticles by Organic Ligands
    Neouze, Marie-Alexandra; Schubert, Ulrich
    Monatshefte fuer Chemie (2008), 139 (3), 183-195CODEN: MOCMB7; ISSN:0026-9247. (Springer Wien)
    A review. Metal or metal oxide nanoparticles possess unique features compared to equiv. larger-scale materials. For applications, it is often necessary to stabilize or functionalize such nanoparticles. Thus, modification of the surface of nanoparticles is an important chem. challenge. In this survey, various possibilities are discussed how nanoparticles can be protected by org. ligands and how these ligands can be used to introduce functionalities. The preparative possibilities include grafting of an already functionalized ligand on the nanoparticle surface, exchanging part or all existing ligands on the nanoparticle surface, or grafting of a ligand on a nanoparticle followed by modification by org. chem. reactions.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXitlamt7o%253D&md5=c87c1fbd172cf021b9ba3862e48ca16b
  29. 29
    Hostetler, M. J.; Green, S. J.; Stokes, J. J.; Murray, R. W. Monolayers in Three Dimensions: Synthesis and Electrochemistry of ω-Functionalized Alkanethiolate-Stabilized Gold Cluster Compounds. J. Am. Chem. Soc. 1996, 118, 4212– 4213,  DOI: 10.1021/ja960198g
    Google Scholar
    29
    Monolayers in three dimensions: synthesis and electrochemistry of ω-functionalized alkanethiolate-stabilized gold cluster compounds
    Hostetler, Michael J.; Green, Stephen J.; Stokes, Jennifer J.; Murray, Royce W.
    Journal of the American Chemical Society (1996), 118 (17), 4212-13CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    The synthesis and characterization of Au cluster compds. contg. a mixt. of alkanethiolate and ω-substituted alkanethiolate ligands are reported. Cluster mols. prepd. with alkanethiolate ligands, according to previous work, have a ∼1.2 nm radius Au core that, modeled as a 309-Au atom cubooctahedron, bears a monolayer ligand skin of ∼95 alkenethiolate chains. The ω-functionalized clusters are synthesized by place exchange reactions in soln. mixts. of alkanethiolate cluster mols. and ω-substituted alkanethiols, where the ω-substituent can be -Br, -CN, vinyl, or ferrocenyl. The reaction products, according to 1H NMR spectroscopy, include cluster mols. with as many as 44 bromide and 15 ferrocenyl ω-substituents. Steric ω-substituent interactions appear to constrain the extent of place exchange. Ferrocenyl-substituted clusters are electroactive in CH2Cl2 solns. as adsorbed monolayers and as diffusing solutes. The mass transport behavior indicates that as many as 15 ferrocene units in a substituted cluster mol. can be oxidized at an electrode surface over a potential range as narrow as that required to oxidize a ferrocene monomer, i.e., the cluster has promise as a reagent that delivers multiple equiv. of redox activity at nearly identical formal potentials. The Au cores of the clusters also exhibit "double layer" charging behavior and are thus true mol. "nanoelectrodes".
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28Xit1amu7o%253D&md5=fba6de9071ffa8f720f2edf2f27f2b1e
  30. 30
    Luo, Z.; Hou, J.; Menin, L.; Ong, Q. K.; Stellacci, F. Evolution of the Ligand Shell Morphology during Ligand Exchange Reactions on Gold Nanoparticles. Angew. Chem., Int. Ed. 2017, 56, 13521– 13525,  DOI: 10.1002/anie.201708190
    Google Scholar
    30
    Evolution of the Ligand Shell Morphology during Ligand Exchange Reactions on Gold Nanoparticles
    Luo, Zhi; Hou, Jing; Menin, Laure; Ong, Quy Khac; Stellacci, Francesco
    Angewandte Chemie, International Edition (2017), 56 (43), 13521-13525CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
    Ligand exchange reactions are used to achieve nanoparticles coated with a mixt. of ligand mols. Currently, nothing is known on the evolution of the morphol. of the ligand shell during the reaction. The authors use a recently developed method (based on MALDI-TOF) to follow the evolution of the ligand shell compn. and morphol. during the reaction. The authors observe the expected evolution in compn. and we find that the ligand shell starts as a random mixt. and gradually evolves towards a patchy morphol. When the compn. has reached a plateau (i.e. when the reaction is generally assumed to be finished), the ligand shell morphol. keeps evolving for days, slowly approaching its equil. configuration.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsV2jtbbE&md5=3f7ec23e1c0ab344c278657b98f2d3b5
  31. 31
    Hurst, S. J.; Lytton-Jean, A. K.; Mirkin, C. A. Maximizing DNA Loading on a Range of Gold Nanoparticle Sizes. Anal. Chem. 2006, 78, 8313– 8318,  DOI: 10.1021/ac0613582
    Google Scholar
    31
    Maximizing DNA Loading on a Range of Gold Nanoparticle Sizes
    Hurst, Sarah J.; Lytton-Jean, Abigail K. R.; Mirkin, Chad A.
    Analytical Chemistry (2006), 78 (24), 8313-8318CODEN: ANCHAM; ISSN:0003-2700. (American Chemical Society)
    The authors have investigated the variables that influence DNA coverage on gold nanoparticles. The effects of salt concn., spacer compn., nanoparticle size, and degree of sonication have been evaluated. Maximum loading was obtained by salt aging the nanoparticles to ∼0.7 M NaCl in the presence of DNA contg. a poly(ethylene glycol) spacer. In addn., DNA loading was substantially increased by sonicating the nanoparticles during the surface loading process. Last, nanoparticles up to 250 nm in diam. were found have ∼2 orders of magnitude higher DNA loading than smaller (13-30 nm) nanoparticles, a consequence of their larger surface area. Stable large particles are attractive for a variety of biodiagnostic assays.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtFyhtrfO&md5=1b1f5ac1386517068d1252b850112211
  32. 32
    Woehrle, G. H.; Brown, L. O.; Hutchison, J. E. Thiol-Functionalized, 1.5-nm Gold Nanoparticles through Ligand Exchange Reactions: Scope and Mechanism of Ligand Exchange. J. Am. Chem. Soc. 2005, 127, 2172– 2183,  DOI: 10.1021/ja0457718
    Google Scholar
    32
    Thiol-Functionalized, 1.5-nm Gold Nanoparticles through Ligand Exchange Reactions: Scope and Mechanism of Ligand Exchange
    Woehrle, Gerd H.; Brown, Leif O.; Hutchison, James E.
    Journal of the American Chemical Society (2005), 127 (7), 2172-2183CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    Ligand exchange reactions of 1.5-nm triphenylphosphine-stabilized nanoparticles with ω-functionalized thiols provides a versatile approach to functionalized, 1.5-nm gold nanoparticles from a single precursor. We describe the broad scope of this method and the first mechanistic investigation of thiol-for-phosphine ligand exchanges. The method is convenient and practical and tolerates a surprisingly wide variety of technol. important functional groups while producing very stable nanoparticles that essentially preserve the small core size and size dispersity of the precursor particle. The mechanistic studies reveal a novel three-stage mechanism that can be used to control the extent of ligand exchange. During the first stage of the exchange, AuCl(PPh3) is liberated, followed by replacement of the remaining phosphine ligands as PPh3 (assisted by gold complexes in soln.). The final stage involves completion and reorganization of the thiol-based ligand shell.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXmslWjsA%253D%253D&md5=22c2b3772b041df9a0e7b43ce580c9e5
  33. 33
    Shichibu, Y.; Negishi, Y.; Tsukuda, T.; Teranishi, T. Large-Scale Synthesis of Thiolated Au25 Clusters via Ligand Exchange Reactions of Phosphine-Stabilized Au11 Clusters. J. Am. Chem. Soc. 2005, 127, 13464– 13465,  DOI: 10.1021/ja053915s
    Google Scholar
    33
    Large-Scale Synthesis of Thiolated Au25 Clusters via Ligand Exchange Reactions of Phosphine-Stabilized Au11 Clusters
    Shichibu, Yukatsu; Negishi, Yuichi; Tsukuda, Tatsuya; Teranishi, Toshiharu
    Journal of the American Chemical Society (2005), 127 (39), 13464-13465CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
    Phosphine-stabilized Au11 clusters in CHCl3 were reacted with glutathione (GSH) in H2O under a N2 atm. The resulting Au:SG clusters exhibit an optical absorption spectrum similar to that of Au25(SG)18, which was isolated as one of the major products from chem. prepd. Au:SG clusters (Negishi, Y. et al., 2005). Rigorous characterization by optical spectroscopy, electrospray ionization mass spectrometry, and polyacrylamide gel electrophoresis confirms that the Au25(SG)18 clusters were selectively obtained on the sub-100 mg scale by ligand exchange reaction under aerobic conditions. The ligand exchange strategy offers a practical and convenient method of synthesizing thiolated Au25 clusters on a large scale.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXpsleqtbc%253D&md5=e4409c1ceb3760ec45a4bb47ecb6c7d2
  34. 34
    Gittins, D.; Caruso, F. Spontaneous Phase Transfer of Nanoparticulate Metals from Organic to Aqueous Media. Angew. Chem., Int. Ed. 2001, 40, 3001– 3004,  DOI: 10.1002/1521-3773(20010817)40:16<3001::AID-ANIE3001>3.0.CO;2-5
    Google Scholar
    34
    Spontaneous phase transfer of nanoparticulate metals from organic to aqueous media
    Gittins, David I.; Caruso, Frank
    Angewandte Chemie, International Edition (2001), 40 (16), 3001-3004CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH)
    A general method to efficiently transfer gold or palladium nanoparticles was developed. The method concerns the transfer from an org. solvent (in this case, toluene) to water. The method includes the following steps: prepn. of the metal nanoparticles in toluene by NaBH4 redn. of HAuCl4 or Na2PdCl4; phase transfer to water after addn. of 4-dimethylaminopyridine or an tetraalkyl ammonium salt.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXms1GrtLc%253D&md5=89f8237322967059b1bafa344632c4c9
  35. 35
    Rucareanu, S.; Gandubert, V. J.; Lennox, R. B. 4-(N,N-Dimethylamino)pyridine-Protected Au Nanoparticles: Versatile Precursors for Water- and Organic-Soluble Gold Nanoparticles. Chem. Mater. 2006, 18, 4674– 4680,  DOI: 10.1021/cm060793+
    Google Scholar
    35
    4-(N,N-Dimethylamino)pyridine-Protected Au Nanoparticles: Versatile Precursors for Water- and Organic-Soluble Gold Nanoparticles
    Rucareanu, Simona; Gandubert, Valerie J.; Lennox, R. Bruce
    Chemistry of Materials (2006), 18 (19), 4674-4680CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)
    Ligand-exchange reactions of 4-(N,N-dimethylamino)pyridine-capped gold nanoparticles (DMAP-Au NP) with functionalized thiols (RSH) were investigated. A simple, convenient, and facile synthesis method was developed. An important feature of this method is its requirement of only very modest quantities of excess thiol ligand. DMAP-Au NP prove to be versatile precursors for both water- and org.-sol. gold NP. DMAP is readily displaced by various functionalized thiols ranging from mercaptocarboxylic acids to ferrocene-terminated thiols. UV-vis spectroscopy and transmission electron microscopy (TEM) confirm that the mean diam. and the size dispersity of the initial DMAP-Au NP were retained upon ligand exchange. The RS-Au NP thus prepd. were efficiently purified by gel permeation chromatog. (GPC) with neither residual DMAP nor RSH detected in the final product.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xoslalurs%253D&md5=c94989a5375149b7344a5c79ee5f90ba
  36. 36
    Manea, F.; Bindoli, C.; Polizzi, S.; Lay, L.; Scrimin, P. Expeditious Synthesis of Water-Soluble, Monolayer-Protected Gold Nanoparticles of Controlled Size and Monolayer Composition. Langmuir 2008, 24, 4120– 4124,  DOI: 10.1021/la703558y
    Google Scholar
    36
    Expeditious synthesis of water-soluble, monolayer-protected gold nanoparticles of controlled size and monolayer composition
    Manea, Flavio; Bindoli, Cristiano; Polizzi, Stefano; Lay, Luigi; Scrimin, Paolo
    Langmuir (2008), 24 (8), 4120-4124CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
    A protocol is reported for the prepn. of water-sol., thiol-monolayer-protected Au nanoparticles where dioctylamine was used as a stabilizing agent when the Au cluster is formed by using the two-phase Brust and Schiffrin procedure (1994). The amt. of amine controls the size of the nanoparticles in the 1.9-8.9 nm diam. range. The final stabilization of the Au clusters by addn. of functionalized thiols was performed under mild conditions compatible with most biomols. The procedure is suitable for a wide variety of functional groups present in the thiol and allows use of thiol mixts. with a precise control of their compn. in the monolayer. As a proof of the principle, examples of nanoparticles protected with thiols comprising functional groups ranging from polyethers, saccharides, polyamines and ammonium ions are reported.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXjtlOjsb4%253D&md5=54fb5aefa8364db309453d5dd1d951ac
  37. 37
    Brinas, R. P.; Maetani, M.; Barchi, J. J., Jr. A Survey of Place-Exchange Reaction for the Preparation of Water-Soluble Gold Nanoparticles. J. Colloid Interface Sci. 2013, 392, 415– 421,  DOI: 10.1016/j.jcis.2012.06.042
    Google Scholar
    There is no corresponding record for this reference.
  38. 38
    Wilcoxon, J. P.; Provencio, P. Etching and Aging Effects in Nanosize Au Clusters Investigated Using High-Resolution Size-Exclusion Chromatography. J. Phys. Chem. B 2003, 107, 12949– 12957,  DOI: 10.1021/jp027575y
    Google Scholar
    38
    Etching and Aging Effects in Nanosize Au Clusters Investigated Using High-Resolution Size-Exclusion Chromatography
    Wilcoxon, Jess P.; Provencio, Paula
    Journal of Physical Chemistry B (2003), 107 (47), 12949-12957CODEN: JPCBFK; ISSN:1520-6106. (American Chemical Society)
    The authors report expts. using high-resoln. size exclusion chromatog. (HRSEC), dynamic light scattering, and TEM to study the effects of aging of Au nanoclusters in the presence of surfactant ligands. The authors 1st describe observations of the role of thiols as etchants to produce clusters in a micelle-free synthesis by redn. of a metal-org. precursor. Clusters with large abundances are identified using HRSEC, and their sizes and optical properties are reported. The smallest, Dc ∼ 1 nm mol. sized Au clusters, with ∼1 closed at. shell, N ∼ 13 atoms, have nonclassical features in their room temp. absorbance spectra. The other dominant sub-populations also correspond closely to closed-shell structural stabilities. Contrary to the expectation that aging in soln. will always broaden the size dispersion and increase the av. size (Ostwald ripening), a narrowing of the size dispersion and change in av. size can occur with time under ambient conditions. In the presence of various chain length alkanethiols, an etching and size decrease usually occurs; in the case of weakly bound alkylated poly(ethylene oxide) surfactants, an increase in size with time is obsd.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXosFWls7o%253D&md5=95c43cb21cc53357b2ac737efe2f8b80
  39. 39
    Shichibu, Y.; Negishi, Y.; Tsunoyama, H.; Kanehara, M.; Teranishi, T.; Tsukuda, T. Extremely High Stability of Glutathionate-Protected Au25 Clusters Against Core Etching. Small 2007, 3, 835– 839,  DOI: 10.1002/smll.200600611
    Google Scholar
    39
    Extremely high stability of glutathionate-protected Au25 clusters against core etching
    Shichibu, Yukatsu; Negishi, Yuichi; Tsunoyama, Hironori; Kanehara, Masayuki; Teranishi, Toshiharu; Tsukuda, Tatsuya
    Small (2007), 3 (5), 835-839CODEN: SMALBC; ISSN:1613-6810. (Wiley-VCH Verlag GmbH & Co. KGaA)
    The core-etching reaction by free glutathione is studied for glutathionate (SG)-protected Aun(SG)m clusters with n = 10-39 and m = 10-24. Only the Au25(SG)18 clusters remain unetched, whereas the Aun(SG)m clusters with n < 25 and n > 25 are transformed into a AuI:SG complex and stable Au25:SG, resp. The selective synthesis of thiolate (SR)-protected Au25:SR on a large scale may be possible.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXls1ajsr8%253D&md5=8137d9a5251b9c3093978cfb63bd0c7a
  40. 40
    Baranov, D.; Kadnikova, E. N. Synthesis and Characterization of Azidoalkyl-Functionalized Gold Nanoparticles as Scaffolds for “Click”-Chemistry Derivatization. J. Mater. Chem. 2011, 21, 6152– 6157,  DOI: 10.1039/c1jm10183h
    Google Scholar
    40
    Synthesis and characterization of azidoalkyl-functionalized gold nanoparticles as scaffolds for "click"-chemistry derivatization
    Baranov, Dmitry; Kadnikova, Ekaterina N.
    Journal of Materials Chemistry (2011), 21 (17), 6152-6157CODEN: JMACEP; ISSN:0959-9428. (Royal Society of Chemistry)
    Water-sol. Au nanoparticles prepd. by the citrate redn. method can be functionalized with 11-azidoundecane-1-thiol in a single-step procedure, which combines phase transfer and ligand exchange. The advantages of the authors' method include high reproducibility, low cost of Au nanoparticle prodn., and rapid and clean ligand exchange, with minimal intermediate steps and none of the laborious efforts. The resulting azido-functionalized nanoparticles were characterized by 1H NMR and UV-visible spectroscopy, and visualized by TEM. The Au nanocrystals preserve their shape and monodispersity after ligand exchange, so are promising scaffolds for further surface engineering via "click" chem. transformations.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXks12gsL0%253D&md5=e5a5e55eb0b66b0946a1c685c9c6b1e1
  41. 41
    Ojea-Jimenez, I.; Romero, F. M.; Bastus, N. G.; Puntes, V. Small Gold Nanoparticles Synthesized with Sodium Citrate and Heavy Water: Insights into the Reaction Mechanism. J. Phys. Chem. C 2010, 114, 1800– 1804,  DOI: 10.1021/jp9091305
    Google Scholar
    41
    Small Gold Nanoparticles Synthesized with Sodium Citrate and Heavy Water: Insights into the Reaction Mechanism
    Ojea-Jimenez, Isaac; Romero, Francisco M.; Bastus, Neus G.; Puntes, Victor
    Journal of Physical Chemistry C (2010), 114 (4), 1800-1804CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)
    The effect of solvent isotopic replacement (H for D) on the size of gold nanoparticles (Au NPs) prepd. by sodium citrate redn. has been investigated. With increasing replacement of water by deuterium oxide, smaller sizes of Au NPs are obtained, which is interpreted as a consequence of a faster redn. A mechanism in which a substitution complex, [AuCl3OCOC(OH)(CH2CO2)2]3-, is formed from [AuCl4]- and citrate ion(3-) prior to its rate-limiting disproportionation into products is suggested. This novel procedure offers an attractive alternative to the existing ones and opens a full range of possibilities for biol. studies.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXjs1ygtQ%253D%253D&md5=ce5e8025b1c81d8178148b652480a9b8
  42. 42
    Milette, J.; Toader, V.; Reven, L.; Lennox, R. B. Tuning the Miscibility of Gold Nanoparticles Dispersed in Liquid Crystals via the Thiol-for-DMAP Reaction. J. Mater. Chem. 2011, 21, 9043– 9050,  DOI: 10.1039/c1jm10553a
    Google Scholar
    42
    Tuning the miscibility of gold nanoparticles dispersed in liquid crystals via the thiol-for-DMAP reaction
    Milette, Jonathan; Toader, Violeta; Reven, Linda; Lennox, R. Bruce
    Journal of Materials Chemistry (2011), 21 (25), 9043-9050CODEN: JMACEP; ISSN:0959-9428. (Royal Society of Chemistry)
    Ligand exchange reactions using 4-5 nm 4-(N,N-dimethylamino)pyridine (DxMAP)-capped Au nanoparticles (AuNPs) formed the basis for synthesizing a family of liq. crystal (LC)-capped NPs for a rationalized miscibility in liq. crystal matrixes. NPs with ligand capping layers composed of Me(CH2)mSH (m = 5, 11) or 4'-(n-mercaptoalkyloxy)biphenyl-4-carbonitriles (CBO(CH2)nSH, n = 8, 12, 16) and their binary mixts. were prepd. The miscibility of the NPs in liq. crystals is sensitive to the ligand chain length and the d. of the LC ligands within the capping layers. Polarized optical microscopy and UV-visible data show that the NPs with only Me(CH2)mSH ligands are either immiscible or only partially disperse in the isotropic phases of 4-n-pentyl-4'-cyanobiphenyl (5CB) and 4-n-octyl-4'-cyanobiphenyl (8CB). NPs with CBO(CH2)nSH (n = 8, 12, 16) ligands or mixed Me(CH2)5SH/CBO(CH2)12SH ligand shells contg. 28% or 70% CBO(CH2)12SH ligand content partly disperse. However, NPs with a 1 : 1 Me(CH2)5SH/CBO(CH2)12SH ratio are completely miscible in isotropic 5CB up to at least 25% Au. In general, the derivatization methodol. developed here for mesogenic ligands provides in a complementary approach to thiol-for-thiol exchange for designing bifunctional AuNPs, offering the advantages of high reproducibility, access to a wide compn. range and no need for large excesses of valuable functionalized ligand.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXnsVWhurg%253D&md5=80c2c57f60eea1d9af5065acbfa59fc0
  43. 43
    Isaacs, S.; Cutler, E.; Park, J.; Lee, T.; Shon, Y. Synthesis of Tetraoctylammonium-Protected Gold Nanoparticles with Improved Stability. Langmuir 2005, 21, 5689– 5692,  DOI: 10.1021/la050656b
    Google Scholar
    43
    Synthesis of Tetraoctylammonium-Protected Gold Nanoparticles with Improved Stability
    Isaacs, Steven R.; Cutler, Erin C.; Park, Joon-Seo; Lee, T. Randall; Shon, Young-Seok
    Langmuir (2005), 21 (13), 5689-5692CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
    This paper shows that an introduction of thiosulfate anions in place of bromide anions greatly improves both chem. and thermal stability of tetraoctylammonium-protected gold nanoparticles. Tetraoctylammonium thiosulfate [(Oct)4N+-O3SS]-protected gold nanoparticles are synthesized by the redn. of (Oct)4N+-AuCl4 to Au(I)-SSO3-, followed by the addn. of sodium borohydride. The presence of thiosulfate anions instead of bromide anions on the surface of gold nanoparticles results in a significant dampening of the surface plasmon band of gold at 526 nm due to the strong interaction between thiosulfate and the gold nanoparticle surface. Cyanide decompn. and heating treatment studies suggest that (Oct)4N+-O3SS-protected nanoparticles have much higher overall stability compared to (Oct)4N+-Br-protected gold nanoparticles.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXktF2rtL0%253D&md5=437a6261ce515058fd1cb1715507187c
  44. 44
    Zhao, P.; Li, N.; Astruc, D. State of the Art in Gold Nanoparticle Synthesis. Coord. Chem. Rev. 2013, 257, 638– 665,  DOI: 10.1016/j.ccr.2012.09.002
    Google Scholar
    44
    State of the art in gold nanoparticle synthesis
    Zhao, Pengxiang; Li, Na; Astruc, Didier
    Coordination Chemistry Reviews (2013), 257 (3-4), 638-665CODEN: CCHRAM; ISSN:0010-8545. (Elsevier B.V.)
    A review. General principles and recent developments in the synthesis of gold nanoparticles (AuNPs) are reviewed. The "in situ" Turkevich-Frens and Brust-Schiffrin methods are still major synthetic routes, with citrate and thiolate ligands, resp., that were improved and extended to macromols. including biomacromols. with a large biomedical potential of optical and theranostic applications. Along this line, however, recently developed seed-growth methods have allowed a precise control of AuNP sizes in a broad range and multiple shapes. AuNPs and core-shell bimetallic MAuNPs loosely stabilized by nitrogen and oxygen atoms of embedding polymers and dendrimers and composite solid-state materials contg. AuNPs with supports including oxides, carbons, mesoporous materials and mol. org. frameworks (MOFs) have attracted much interest because of their catalytic applications.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXntlCmtg%253D%253D&md5=b399d1f3cce2440cf125b0f9394c6e5c
  45. 45
    Mourdikoudis, S.; Liz-Marzán, L. M. Oleylamine in Nanoparticle Synthesis. Chem. Mater. 2013, 25, 1465– 1476,  DOI: 10.1021/cm4000476
    Google Scholar
    45
    Oleylamine in Nanoparticle Synthesis
    Mourdikoudis, Stefanos; Liz-Marzan, Luis M.
    Chemistry of Materials (2013), 25 (9), 1465-1476CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)
    A review. Wet chem. in org. solvents has proven highly efficient for the prepn. of several types of metallic, metal-oxide, and semiconductor nanostructures. This Short Review focuses on the use of oleylamine (OAm) as a versatile reagent for the synthesis of various nanoparticle systems. The ability of OAm to act as a surfactant, solvent, and reducing agent, as a function of other synthesis parameters is described. The specific role of OAm either alone or in combination with other reactants to form nanostructures using a variety of org. or inorg. compds. as precursors is discussed. In certain cases OAm can form complex compds. with the metal ions of the corresponding precursor, leading to metastable compds. that can act as secondary precursors and thus be decompd. in a controlled way to yield nanoparticles. The OAm-stabilized particles can often be dispersed in different org. solvents yielding solns. with enhanced colloidal stability over long times and the potential to find applications in a no. of different fields.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXitlChsb4%253D&md5=f5c775c4fae0ffc3877262337f6a6e91
  46. 46
    Hiramatsu, H.; Osterloh, F. E. A Simple Large-Scale Synthesis of Nearly Monodisperse Gold and Silver Nanoparticles with Adjustable Sizes and with Exchangeable Surfactants. Chem. Mater. 2004, 16, 2509– 2511,  DOI: 10.1021/cm049532v
    Google Scholar
    46
    A Simple Large-Scale Synthesis of Nearly Monodisperse Gold and Silver Nanoparticles with Adjustable Sizes and with Exchangeable Surfactants
    Hiramatsu, Hiroki; Osterloh, Frank E.
    Chemistry of Materials (2004), 16 (13), 2509-2511CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)
    We report an inexpensive, versatile, and very reproducible method for the large-scale synthesis of organoamine-protected gold and silver nanoparticles in the 6-21 nm (Au) and 8-32 nm (Ag) size ranges and with polydispersities as low as 6.9 %.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXktlaitb4%253D&md5=187f478bb9f29c2961ae775bdf11f1b5
  47. 47
    Lau, C. Y.; Duan, H.; Wang, F.; He, C. B.; Low, H. Y.; Yang, J. K. Enhanced Ordering in Gold Nanoparticles Self-Assembly through Excess Free Ligands. Langmuir 2011, 27, 3355– 3360,  DOI: 10.1021/la104786z
    Google Scholar
    47
    Enhanced Ordering in Gold Nanoparticles Self-Assembly through Excess Free Ligands
    Lau, Cindy Y.; Duan, Huigao; Wang, Fuke; He, Chao Bin; Low, Hong Yee; Yang, Joel K. W.
    Langmuir (2011), 27 (7), 3355-3360CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
    Self-assembly of nanometer-sized particles is an elegant and economical approach to achieve dense patterns over large areas beyond the resoln. and throughput capabilities of electron-beam lithog. In this paper, we present results of self-assembly of oleylamine-capped gold nanoparticles with 8.0 ± 0.3 nm diam. into densely packed and well-ordered monolayers with center-to-center distance of ∼11 nm. Self-assembly was done in a Langmuir-Blodgett trough and picked up onto Si substrates. The nanoparticles undesirably assembled within micrometer-sized "droplets" that were org. in nature. However, within these droplets, we obsd. that the addn. of the excess ligand, oleylamine, drastically enhanced the self-assembly of the nanoparticles into monolayers with near-perfect ordering. This approach has the potential use in templated self-assembly of nanoparticles for rearranging poorly ordered assembly into a commensurate prepatterned substrate.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXisVWmtbc%253D&md5=a7a4d5c688d84cd29ae800cd178e4a9b
  48. 48
    Ojea-Jiménez, I.; García-Fernández, L.; Lorenzo, J.; Puntes, V. F. Facile Preparation of Cationic Gold Nanoparticle-Bioconjugates for Cell Penetration and Nuclear Targeting. ACS Nano 2012, 6, 7692– 7702,  DOI: 10.1021/nn3012042
    Google Scholar
    48
    Facile preparation of cationic gold nanoparticle-bioconjugates for cell penetration and nuclear targeting
    Ojea-Jimenez, Isaac; Garcia-Fernandez, Lorena; Lorenzo, Julia; Puntes, Victor F.
    ACS Nano (2012), 6 (9), 7692-7702CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)
    The present work faces the rising demand of cationic particles of different sizes for biol. applications, esp. in gene therapies and nanotoxicol. studies. A simple phase-transfer methodol. has been developed for the functionalization of gold nanoparticles (Au NPs) with a variety of ligands, both cationic and anionic in aq. soln., employing different nanocrystal sizes with narrow size distributions. Successful functionalization has been demonstrated by UV-vis spectroscopy, DLS, ζ-potential, and FTIR spectroscopy characterization of the particles before and after the phase transfer. The intracellular uptake of the differently charged Au NPs functionalized with peptidic biomols. was investigated with human fibroblasts (1BR3G) by ICP-MS anal. of the digested cells and confocal fluorescence microscopy, which showed increased internalization of the cationic bioconjugates. Nuclear targeting could be obsd. by TEM, suggesting that the cationic peptidic biomol. is acting as a nuclear localization signal.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtFGhs73F&md5=08ceeed256ef25bad68de14f6d10c974
  49. 49
    Zhang, T.; Guerin, D.; Alibart, F.; Vuillaume, D.; Lmimouni, K.; Lenfant, S.; Yassin, A.; Oçafrain, M.; Blanchard, P.; Roncali, J. Negative Differential Resistance, Memory, and Reconfigurable Logic Functions Based on Monolayer Devices Derived from Gold Nanoparticles Functionalized with Electropolymerizable TEDOT Units. J. Phys. Chem. C 2017, 121, 10131– 10139,  DOI: 10.1021/acs.jpcc.7b00056
    Google Scholar
    49
    Negative Differential Resistance, Memory, and Reconfigurable Logic Functions Based on Monolayer Devices Derived from Gold Nanoparticles Functionalized with Electropolymerizable TEDOT Units
    Zhang, T.; Guerin, D.; Alibart, F.; Vuillaume, D.; Lmimouni, K.; Lenfant, S.; Yassin, A.; Ocafrain, M.; Blanchard, P.; Roncali, J.
    Journal of Physical Chemistry C (2017), 121 (18), 10131-10139CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)
    The authors report on hybrid memristive devices made of a network of gold nanoparticles (10 nm diam.) functionalized by tailored 3,4-(ethylenedioxy)thiophene (TEDOT) mols., deposited between two planar electrodes with nanometer and micrometer gaps (100 nm to 10 μm apart), and electropolymd. in situ to form a monolayer film of conjugated polymer with embedded gold nanoparticles (AuNPs). Elec. properties of these films exhibit two interesting behaviors: (i) a NDR (neg. differential resistance) behavior with a peak/valley ratio up to 17 and (ii) a memory behavior with an ON/OFF current ratio of ∼103-104. A careful study of the switching dynamics and programming voltage window is conducted demonstrating a nonvolatile memory. The data retention of the ON and OFF states is stable (tested up to 24 h), well controlled by the voltage, and preserved when repeating the switching cycles (800 in this study). The authors demonstrate reconfigurable Boolean functions in multiterminal connected NP/mol. devices.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXlvVGqur8%253D&md5=9c0b9db36c46c78d997f19a45a989980
  50. 50
    Peng, S.; Lee, Y.; Wang, C.; Yin, H.; Dai, S.; Sun, S. A Facile Synthesis of Monodisperse Au Nanoparticles and Their Catalysis of CO Oxidation. Nano Res. 2008, 1, 229– 234,  DOI: 10.1007/s12274-008-8026-3
    Google Scholar
    50
    A facile synthesis of monodisperse Au nanoparticles and their catalysis of CO oxidation
    Peng, Sheng; Lee, Youngmin; Wang, Chao; Yin, Hongfeng; Dai, Sheng; Sun, Shouheng
    Nano Research (2008), 1 (3), 229-234CODEN: NRAEB5; ISSN:1998-0124. (Springer)
    Monodisperse Au nanoparticles (NPs) were prepd. at room temp. via a burst nucleation of Au upon injection of the reducing agent t-butylamine-borane complex into a 1, 2,3,4-tetrahydronaphthalene soln. of HAuCl4.3H2O in the presence of oleylamine. The as-prepd. Au NPs show size-dependent surface plasmonic properties between 520 and 530 nm. They adopt an icosahedral shape and are polycryst. with multiple-twinned structures. When deposited on a graphitized porous carbon support, the NPs are highly active for CO oxidn., showing 100% CO conversion at -45°.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtFSjtrvE&md5=947e041704eee598d98afa7be9b38fa3
  51. 51
    Shen, C.; Hui, C.; Yang, T.; Xiao, C.; Tian, J.; Bao, L.; Chen, S.; Ding, H.; Gao, H. Monodisperse Noble-Metal Nanoparticles and Their Surface Enhanced Raman Scattering Properties. Chem. Mater. 2008, 20, 6939– 6944,  DOI: 10.1021/cm800882n
    Google Scholar
    51
    Monodisperse Noble-Metal Nanoparticles and Their Surface Enhanced Raman Scattering Properties
    Shen, Chengmin; Hui, Chao; Yang, Tianzhong; Xiao, Congwen; Tian, Jifa; Bao, Lihong; Chen, Shutang; Ding, Hao; Gao, Hongjun
    Chemistry of Materials (2008), 20 (22), 6939-6944CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)
    Monodisperse Au, Ag, and Au3Pd nanoparticles (NPs) with narrow size distribution are prepd. by direct reaction of the related metal salt with oleylamine in toluene. Oleylamine serves as both a reducing agent and a surfactant in the synthesis. The sizes and shape of these NPs are tuned by reaction temps. The hydrophobic oleylamine-coated NPs can be made water sol. by replacing oleylamine with 3-mercaptopropionic acid. Both surface plasmonic resonance (SPR) and surface enhanced Raman scattering (SERS) obsd. from the Au and Ag NPs are NP size- and surface-dependent.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtlSntbjE&md5=fededcedfe8dec139110092263c74a58
  52. 52
    Kluenker, M.; Mondeshki, M.; Nawaz Tahir, M.; Tremel, W. Monitoring Thiol-Ligand Exchange on Au Nanoparticle Surfaces. Langmuir 2018, 34, 1700– 1710,  DOI: 10.1021/acs.langmuir.7b04015
    Google Scholar
    52
    Monitoring Thiol-Ligand Exchange on Au Nanoparticle Surfaces
    Kluenker, Martin; Mondeshki, Mihail; Nawaz Tahir, Muhammad; Tremel, Wolfgang
    Langmuir (2018), 34 (4), 1700-1710CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
    Surface functionalization of nanoparticles (NPs) plays a crucial role in particle soly. and reactivity. It is vital for particle nucleation and growth as well as for catalysis. This raises the quest for functionalization efficiency and new approaches to probe the degree of surface coverage. The authors present an (in situ) proton NMR (1H NMR) study on the ligand exchange of oleylamine by 1-octadecanethiol as a function of the particle size and repeated functionalization on Au NPs. Ligand exchange is an equil. reaction assocd. with Nernst distribution, which often leads to incomplete surface functionalization following "std." literature protocols. The surface coverage with the ligand depends on the (i) repeated exchange reactions with large ligand excess, (ii) size of NPs, i.e., the surface curvature and reactivity, and (iii) mol. size of the ligand. As resonance shifts and extensive line broadening during and after the ligand exchange impede the evaluation of 1H NMR spectra, one- and two-dimensional 19F NMR techniques (correlation spectroscopy and diffusion ordered spectroscopy) with 1H,1H,2H,2H-perfluorodecanthiol as the fluorinated thiol ligand were employed to study the reactions. The enhanced resoln. assocd. with the spectral range of the 19F nucleus allowed carrying out a site-specific study of thiol chemisorption. The widths and shifts of the resonance signals of the different fluorinated carbon moieties were correlated with the distance to the thiol anchor group. In addn., the diffusion anal. revealed that moieties closer to the NP surface are characterized by a broader diffusion coeff. distribution as well as slower diffusion.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXksVKlug%253D%253D&md5=704f5450a3f59b0ebca3ada2b0716683
  53. 53
    Malicki, M.; Hales, J. M.; Rumi, M.; Barlow, S.; McClary, L.; Marder, S. R.; Perry, J. W. Excited-State Dynamics and Dye-Dye Interactions in Dye-Coated Gold Nanoparticles with Varying Alkyl Spacer Lengths. Phys. Chem. Chem. Phys. 2010, 12, 6267– 6277,  DOI: 10.1039/b926938j
    Google Scholar
    There is no corresponding record for this reference.
  54. 54
    Köhntopp, A.; Dabrowski, A.; Malicki, M.; Temps, F. Photoisomerisation and Ligand-Controlled Reversible Aggregation of Azobenzene-Functionalised Gold Nanoparticles. Chem. Commun. 2014, 50, 10105– 10107,  DOI: 10.1039/C4CC02250E
    Google Scholar
    54
    Photoisomerisation and ligand-controlled reversible aggregation of azobenzene-functionalised gold nanoparticles
    Kohntopp Anja; Dabrowski Alexandra; Malicki Michal; Temps Friedrich
    Chemical communications (Cambridge, England) (2014), 50 (70), 10105-7 ISSN:.
    The photochemical behaviour of functionalised gold nanoparticles (AuNPs) carrying azobenzenethiolate-alkylthiolate monolayers was investigated. Repeated trans-cis and cis-trans isomerisation cycles could be performed in all cases with high efficiency. Reversible photoinduced aggregation was observed when azothiolates with long alkyl spacers (≥C7) were combined with short (C5) alkylthiolate coligands. The choice of a coligand thus offers control over the aggregation properties of the nanoparticles.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2cbksl2mtw%253D%253D&md5=f39babf7b73acb89fac5db54f88be944
  55. 55
    Chu, Z.; Han, Y.; Kral, P.; Klajn, R. ”Precipitation on Nanoparticles”: Attractive Intermolecular Interactions Stabilize Specific Ligand Ratios on the Surfaces of Nanoparticles. Angew. Chem., Int. Ed. 2018, 57, 1– 6,  DOI: 10.1002/anie.201800673
    Google Scholar
    There is no corresponding record for this reference.
  56. 56
    Liu, X.; Hu, Y.; Stellacci, F. Mixed-Ligand Nanoparticles as Supramolecular Receptors. Small 2011, 7, 1961– 1966,  DOI: 10.1002/smll.201100386
    Google Scholar
    56
    Mixed-Ligand Nanoparticles as Supramolecular Receptors
    Liu, Xiang; Hu, Ying; Stellacci, Francesco
    Small (2011), 7 (14), 1961-1966CODEN: SMALBC; ISSN:1613-6810. (Wiley-VCH Verlag GmbH & Co. KGaA)
    Mixed-ligand-coated Au nanoparticles were synthesized using a naphthalene-terminated thiol (MNT) ligand and hexanethiol (HT). The mixed ligands self-assemble at the surface of nanoparticles forming a structure that interacts with PAHs through π-π interactions. Whereas the corresponding homoligand particles do not interact with PAHs in any detectable way, the mixed-ligand particles all have good binding ability to PAHs; specifically Au-MNT0.50HT0.50 binds to pyrene with a binding const. of 6.49 ± 5.71 × 104 M-1. Overall, mixed ligand-coated Au nanoparticles are versatile receptors for various PAHs. These easy-to-synthesize and easy-to-tailor particles can be used potentially for the detection and clean-up of PAH pollutants.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXovVert78%253D&md5=381714a92fef76835a56b251a0b6ee70
  57. 57
    van Lehn, R. C.; Ricci, M.; Silva, P. H.; Andreozzi, P.; Reguera, J.; Voïtchovsky, K.; Stellacci, F.; Alexander-Katz, A. Lipid Tail Protrusions Mediate the Insertion of Nanoparticles into Model Cell Membranes. Nat. Commun. 2014, 5, 4482,  DOI: 10.1038/ncomms5482
    Google Scholar
    57
    Lipid tail protrusions mediate the insertion of nanoparticles into model cell membranes
    Van Lehn, Reid C.; Ricci, Maria; Silva, Paulo H. J.; Andreozzi, Patrizia; Reguera, Javier; Voitchovsky, Kislon; Stellacci, Francesco; Alexander-Katz, Alfredo
    Nature Communications (2014), 5 (), 4482CODEN: NCAOBW; ISSN:2041-1723. (Nature Publishing Group)
    Recent work has demonstrated that charged gold nanoparticles (AuNPs) protected by an amphiphilic org. monolayer can spontaneously insert into the core of lipid bilayers to minimize the exposure of hydrophobic surface area to water. However, the kinetic pathway to reach the thermodynamically stable transmembrane configuration is unknown. Here, we use unbiased atomistic simulations to show the pathway by which AuNPs spontaneously insert into bilayers and confirm the results exptl. on supported lipid bilayers. The crit. step during this process is hydrophobic-hydrophobic contact between the core of the bilayer and the monolayer of the AuNP that requires the stochastic protrusion of an aliph. lipid tail into soln. This last phenomenon is enhanced in the presence of high bilayer curvature and closely resembles the putative pre-stalk transition state for vesicle fusion. To the best of our knowledge, this work provides the first demonstration of vesicle fusion-like behavior in an amphiphilic nanoparticle system.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXksVemu74%253D&md5=57dea1fc7554e69fae0dd6881d417867
  58. 58
    Harkness, K. M.; Hixson, B. C.; Fenn, L. S.; Turner, B. N.; Rape, A. C.; Simpson, C. A.; Huffman, B. J.; Okoli, T. C.; McLean, J. A.; Cliffel, D. E. A Structural Mass Spectrometry Strategy for the Relative Quantitation of Ligands on Mixed Monolayer-Protected Gold Nanoparticles. Anal. Chem. 2010, 82, 9268– 9274,  DOI: 10.1021/ac102175z
    Google Scholar
    58
    A Structural Mass Spectrometry Strategy for the Relative Quantitation of Ligands on Mixed Monolayer-Protected Gold Nanoparticles
    Harkness, Kellen M.; Hixson, Brian C.; Fenn, Larissa S.; Turner, Brian N.; Rape, Amanda C.; Simpson, Carrie A.; Huffman, Brian J.; Okoli, Tracy C.; McLean, John A.; Cliffel, David E.
    Analytical Chemistry (Washington, DC, United States) (2010), 82 (22), 9268-9274CODEN: ANCHAM; ISSN:0003-2700. (American Chemical Society)
    It is becoming increasingly common to use Au nanoparticles (AuNPs) protected by a heterogeneous mixt. of thiolate ligands, but many ligand mixts. on AuNPs cannot be properly characterized due to the inherent limitations of commonly used spectroscopic techniques. Using ion mobility-mass spectrometry (IM-MS), the authors have developed a strategy that allows measurement of the relative quantity of ligands on AuNP surfaces. This strategy is used for the characterization of 3 samples of mixed-ligand AuNPs: tiopronin:glutathione (av. diam. 2.5 nm), octanethiol:decanethiol (av. diam. 3.6 nm), and tiopronin:11-mercaptoundecyl(poly ethylene glycol) (av. diam. 2.5 nm). For validation purposes, the results obtained for tiopronin:glutathione AuNPs were compared to parallel measurements using NMR spectroscopy and mass spectrometry (MS) without ion mobility sepn. Relative quantitation measurements for NMR and IM-MS were in excellent agreement, with an av. difference of <1% relative abundance. IM-MS and MS without ion mobility sepn. were not comparable, due to a lack of ion signals for MS. The other 2 mixed-ligand AuNPs provide examples of measurements that cannot be performed using NMR spectroscopy.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtlait7rI&md5=2abf76886e4f556c306657bd84a73dc9
  59. 59
    Badia, A.; Gao, W.; Singh, S.; Demers, L.; Cuccia, L.; Reven, L. Structure and chain dynamics of alkanethiol-capped gold colloids. Langmuir 1996, 12, 1262– 1269,  DOI: 10.1021/la9510487
    Google Scholar
    59
    Structure and Chain Dynamics of Alkanethiol-Capped Gold Colloids
    Badia, A.; Gao, W.; Singh, S.; Demers, L.; Cuccia, L.; Reven, L.
    Langmuir (1996), 12 (5), 1262-9CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
    The structure and dynamical behavior of short and long chain alkanethiols, CH3(CH2)7SH and CH3(CH)17SH, and of a hydroxyalkanethiol, HO(CH2)16SH, adsorbed onto gold nanoparticles were studied by variable temp. solid-state 13C NMR spectroscopy. In both the soln. and solid state, the resonances of the first three carbons next to the sulfur headgroup disappear upon binding to the gold, indicating a strong interaction with the surface. A 13C-enriched sample, CH3(CH2)12*CH2SH/gold, displays a broad resonance centered at 42 ppm for the carbon next to the sulfur headgroup. Whereas the solid-state 13C shifts of CH3(CH2)7SH/gold are essentially the same as in soln., the methylene carbons of CH3(CH2)17SH and HO(CH2)16SH/gold shift downfield by 4.5 ppm in the solid state, indicating that the chains crystallize into an extended all-trans conformation. The high conformational order, along with reduced methylene proton line widths in the CH3(CH)17SH/gold sample, indicates that the chains are undergoing large-amplitude motions about their long axes. Mol. mobility increases toward the unbound ends which have a higher population of gauche conformers. Relaxation measurements show the coexistence of motionally restricted all-trans chains and a smaller population of liq.-like conformationally disordered chains in CH3(CH2)17SH/gold at room temp. The two types of chains are proposed to arise from close packing of the gold colloidal spheres, resulting in interstitial spaces and regions where chains of neighboring colloids can interdigitate to produce ordered domains. Phase transitions of the thiol-capped gold nanocrystals, which are detected by differential scanning calorimetry, are shown to involve a reversible disordering of the alkyl chains.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XhtVCjt7o%253D&md5=3b6d40377060f5c2e5a8083c7a5dccb5
  60. 60
    Smith, A. M.; Marbella, L. E.; Johnston, K. A.; Hartmann, M. J.; Crawford, S. E.; Kozycz, L. M.; Seferos, D. S.; Millstone, J. E. Quantitative Analysis of Thiolated Ligand Exchange on Gold Nanoparticles Monitored by 1H NMR Spectroscopy. Anal. Chem. 2015, 87, 2771– 2778,  DOI: 10.1021/ac504081k
    Google Scholar
    60
    Quantitative Analysis of Thiolated Ligand Exchange on Gold Nanoparticles Monitored by 1H NMR Spectroscopy
    Smith, Ashley M.; Marbella, Lauren E.; Johnston, Kathryn A.; Hartmann, Michael J.; Crawford, Scott E.; Kozycz, Lisa M.; Seferos, Dwight S.; Millstone, Jill E.
    Analytical Chemistry (Washington, DC, United States) (2015), 87 (5), 2771-2778CODEN: ANCHAM; ISSN:0003-2700. (American Chemical Society)
    The authors use NMR spectroscopy methods to quantify the extent of ligand exchange between different types of thiolated mols. on the surface of gold nanoparticles. Specifically, the authors det. ligand d. values for single-moiety ligand shells and then use these data to describe ligand exchange behavior with a 2nd, thiolated mol. Using these techniques, the authors identify trends in gold nanoparticle functionalization efficiency with respect to ligand type, concn., and reaction time as well as distinguish between functionalization pathways where the new ligand may either replace the existing ligand shell (exchange) or add to it (backfilling). Specifically, gold nanoparticles functionalized with thiolated macromols., such as poly(ethylene glycol) (1 kDa), exhibit ligand exchange efficiencies ranging from 70% to 95% depending on the structure of the incoming ligand. Conversely, gold nanoparticles functionalized with small-mol. thiolated ligands exhibit exchange efficiencies ≥2% when exposed to thiolated mols. under identical exchange conditions. Taken together, the reported results provide advances in the fundamental understanding of mixed ligand shell formation and will be important for the prepn. of gold nanoparticles in a variety of biomedical, optoelectronic, and catalytic applications.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXitlKku7Y%253D&md5=af058a3c89841630643b42c9bc642632
  61. 61
    Goldmann, C.; Ribot, F.; Peiretti, L. F.; Quaino, P.; Tielens, F.; Sanchez, C.; Chanéac, C.; Portehault, D. Quantified Binding Scale of Competing Ligands at the Surface of Gold Nanoparticles: The Role of Entropy and Intermolecular Forces. Small 2017, 13, 1604028,  DOI: 10.1002/smll.201604028
    Google Scholar
    There is no corresponding record for this reference.
  62. 62
    Luo, Z.; Marson, D.; Ong, Q. K.; Loiudice, A.; Kohlbrecher, J.; Radulescu, A.; Krause-Heuer, A.; Darwish, T.; Balog, S.; Buonsanti, R.; Svergun, D. I.; Posocco, P.; Stellacci, F. Quantitative 3D Determination of Self-Assembled Structures on Nanoparticles Using Small Angle Neutron Scattering. Nat. Commun. 2018, 9, 1343,  DOI: 10.1038/s41467-018-03699-7
    Google Scholar
    62
    Quantitative 3D determination of self-assembled structures on nanoparticles using small angle neutron scattering
    Luo Zhi; Ong Quy K; Stellacci Francesco; Marson Domenico; Posocco Paola; Loiudice Anna; Buonsanti Raffaella; Kohlbrecher Joachim; Radulescu Aurel; Krause-Heuer Anwen; Darwish Tamim; Balog Sandor; Svergun Dmitri I
    Nature communications (2018), 9 (1), 1343 ISSN:.
    The ligand shell (LS) determines a number of nanoparticles' properties. Nanoparticles' cores can be accurately characterized; yet the structure of the LS, when composed of mixture of molecules, can be described only qualitatively (e.g., patchy, Janus, and random). Here we show that quantitative description of the LS' morphology of monodisperse nanoparticles can be obtained using small-angle neutron scattering (SANS), measured at multiple contrasts, achieved by either ligand or solvent deuteration. Three-dimensional models of the nanoparticles' core and LS are generated using an ab initio reconstruction method. Characteristic length scales extracted from the models are compared with simulations. We also characterize the evolution of the LS upon thermal annealing, and investigate the LS morphology of mixed-ligand copper and silver nanoparticles as well as gold nanoparticles coated with ternary mixtures. Our results suggest that SANS combined with multiphase modeling is a versatile approach for the characterization of nanoparticles' LS.
    >> More from SciFinder ®
    https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1MjgsVSltQ%253D%253D&md5=ee2b08eec010532488199ea0ed6369a7

Cited By

ARTICLE SECTIONS
Jump To

This article is cited by 24 publications.

  1. Palida Pongsanon, Yoshiko Oota, Akifumi Kawamura, Hideya Kawasaki, Takashi Miyata. Controllable Catalytic Activity of Temperature-Responsive Polymer Hybrid Microgels Designed Using a Gold Nanoparticle Monomer with Polymerizable Groups. Macromolecules 2023, 56 (23) , 9853-9865. https://doi.org/10.1021/acs.macromol.3c01659
  2. Farzin Mashali, Colin M. Basham, Xufeng Xu, Camilla Servidio, Paulo H. Jacob Silva, Francesco Stellacci, Stephen A. Sarles. Simultaneous Electrophysiology and Imaging Reveal Changes in Lipid Membrane Thickness and Tension upon Uptake of Amphiphilic Gold Nanoparticles. Langmuir 2023, 39 (42) , 15031-15045. https://doi.org/10.1021/acs.langmuir.3c01973
  3. Stefan Borsley, William Edwards, Ioulia K. Mati, Guillaume Poss, Marta Diez-Castellnou, Nicolas Marro, Euan R. Kay. A General One-Step Synthesis of Alkanethiyl-Stabilized Gold Nanoparticles with Control over Core Size and Monolayer Functionality. Chemistry of Materials 2023, 35 (15) , 6168-6177. https://doi.org/10.1021/acs.chemmater.3c01506
  4. Niamh Mac Fhionnlaoich, Stephen Schrettl, Nicholas B. Tito, Ye Yang, Malavika Nair, Luis A. Serrano, Kellen Harkness, Paulo Jacob Silva, Holger Frauenrath, Francesca Serra, W. Craig Carter, Francesco Stellacci, Stefan Guldin. Reversible Microscale Assembly of Nanoparticles Driven by the Phase Transition of a Thermotropic Liquid Crystal. ACS Nano 2023, 17 (11) , 9906-9918. https://doi.org/10.1021/acsnano.2c09203
  5. Yinan Fan, Adrien Girard, Michael Waals, Caroline Salzemann, Alexa Courty. Ag@Pt Core–Shell Nanoparticles for Plasmonic Catalysis. ACS Applied Nano Materials 2023, 6 (2) , 1193-1202. https://doi.org/10.1021/acsanm.2c04767
  6. Mengxue Zhang, Taylor Larison, Sidong Tu, Olga Kuksenok, Morgan Stefik. Effect of Fluorophobic Character upon Switching Nanoparticles in Polymer Films from Aggregated to Dispersed States Using Immersion Annealing. ACS Applied Polymer Materials 2022, 4 (10) , 7042-7053. https://doi.org/10.1021/acsapm.2c00968
  7. Jia Liu, Jiatao Zhang. Nanointerface Chemistry: Lattice-Mismatch-Directed Synthesis and Application of Hybrid Nanocrystals. Chemical Reviews 2020, 120 (4) , 2123-2170. https://doi.org/10.1021/acs.chemrev.9b00443
  8. Zonglin Chu, Yanxiao Han, Tong Bian, Soumen De, Petr Král, Rafal Klajn. Supramolecular Control of Azobenzene Switching on Nanoparticles. Journal of the American Chemical Society 2019, 141 (5) , 1949-1960. https://doi.org/10.1021/jacs.8b09638
  9. Pedro D. Ortiz, Judith Castillo-Rodriguez, Ximena Zarate, Rudy Martin-Trasanco, Mónica Benito, Ignasi Mata, Elies Molins, Eduardo Schott. Synthesis of Au Nanoparticles Assisted by Linker-Modified TiO2 Nanoparticles. Langmuir 2018, 34 (32) , 9402-9409. https://doi.org/10.1021/acs.langmuir.7b04195
  10. V. Gopalakrishnan, R. Singaravelan. Enhanced antidiabetic and antioxidant properties of gold nanoparticles green synthesized using blossom extract of Azadirachta indica: In vitro studies. Inorganic Chemistry Communications 2023, 158 , 111609. https://doi.org/10.1016/j.inoche.2023.111609
  11. D. Slavov, I. Bliznakova, Y. Andreeva, Z. Peshev. Application of coating based on 5 nm octadecylamine-functionalized gold-nanoparticles for protecting the spin-polarization of atoms confined in a vacuum cell. Optical Materials 2023, 142 , 113978. https://doi.org/10.1016/j.optmat.2023.113978
  12. Xinna Bai, Weifang Gong, Yaxin Guo, Di Zhu, Xuemei Li. Detection of saxitoxin by a SERS aptamer sensor based on enzyme cycle amplification technology. The Analyst 2023, 148 (10) , 2327-2334. https://doi.org/10.1039/D3AN00330B
  13. Emanuele Petretto, Quy K. Ong, Francesca Olgiati, Ting Mao, Pablo Campomanes, Francesco Stellacci, Stefano Vanni. Monovalent ion-mediated charge–charge interactions drive aggregation of surface-functionalized gold nanoparticles. Nanoscale 2022, 14 (40) , 15181-15192. https://doi.org/10.1039/D2NR02824G
  14. Ryan D. Mellor, Ijeoma F. Uchegbu. Ultrasmall-in-Nano: Why Size Matters. Nanomaterials 2022, 12 (14) , 2476. https://doi.org/10.3390/nano12142476
  15. Quy Ong, Ting Mao, Neda Iranpour Anaraki, Łukasz Richter, Carla Malinverni, Xufeng Xu, Francesca Olgiati, Paulo Henrique Jacob Silva, Anna Murello, Antonia Neels, Davide Demurtas, Seishi Shimizu, Francesco Stellacci. Cryogenic electron tomography to determine thermodynamic quantities for nanoparticle dispersions. Materials Horizons 2022, 9 (1) , 303-311. https://doi.org/10.1039/D1MH01461G
  16. Mahboob Alam. Photocatalytic activity of biogenic zinc oxide nanoparticles: In vitro antimicrobial, biocompatibility, and molecular docking studies. Nanotechnology Reviews 2021, 10 (1) , 1079-1091. https://doi.org/10.1515/ntrev-2021-0069
  17. Rituraj Borah, Rajeshreddy Ninakanti, Gert Nuyts, Hannelore Peeters, Adrián Pedrazo‐Tardajos, Silvia Nuti, Christophe Vande Velde, Karolien De Wael, Silvia Lenaerts, Sara Bals, Sammy W. Verbruggen. Selectivity in the Ligand Functionalization of Photocatalytic Metal Oxide Nanoparticles for Phase Transfer and Self‐Assembly Applications. Chemistry – A European Journal 2021, 27 (35) , 9011-9021. https://doi.org/10.1002/chem.202100029
  18. He Huang, Hendrik du Toit, Luca Panariello, Luca Mazzei, Asterios Gavriilidis. Continuous synthesis of gold nanoparticles in micro- and millifluidic systems. Physical Sciences Reviews 2021, 6 (3) https://doi.org/10.1515/psr-2017-0119
  19. Giacomo Filippini, Paolo Pengo, Susanna Bosi, Giulio Ragazzon, Lucia Pasquato, Maurizio Prato. Engineering Functional Nanomaterials Through the Amino Group. 2021, 285-340. https://doi.org/10.1002/9783527826186.ch8
  20. Jakub W Trzciński, Luca Panariello, Maximilian O Besenhard, Ye Yang, Asterios Gavriilidis, Stefan Guldin. Synthetic guidelines for the precision engineering of gold nanoparticles. Current Opinion in Chemical Engineering 2020, 29 , 59-66. https://doi.org/10.1016/j.coche.2020.05.004
  21. Ye Yang, Suiyang Liao, Zhi Luo, Runzhang Qi, Niamh Mac Fhionnlaoich, Francesco Stellacci, Stefan Guldin. Comparative characterisation of non-monodisperse gold nanoparticle populations by X-ray scattering and electron microscopy. Nanoscale 2020, 12 (22) , 12007-12013. https://doi.org/10.1039/C9NR09481D
  22. Federico De Biasi, Fabrizio Mancin, Federico Rastrelli. Nanoparticle-assisted NMR spectroscopy: A chemosensing perspective. Progress in Nuclear Magnetic Resonance Spectroscopy 2020, 117 , 70-88. https://doi.org/10.1016/j.pnmrs.2019.12.001
  23. Biagio De Angelis, Nicoletta Depalo, Francesca Petronella, Concetta Quintarelli, M. Lucia Curri, Roberto Pani, Antonella Calogero, Franco Locatelli, Luciano De Sio. Stimuli-responsive nanoparticle-assisted immunotherapy: a new weapon against solid tumours. Journal of Materials Chemistry B 2020, 8 (9) , 1823-1840. https://doi.org/10.1039/C9TB02246E
  24. Ye Yang, Guillaume Poss, Yini Weng, Runzhang Qi, Hanrui Zheng, Nikolaos Nianias, Euan R. Kay, Stefan Guldin. Probing the interaction of nanoparticles with small molecules in real time via quartz crystal microbalance monitoring. Nanoscale 2019, 11 (23) , 11107-11113. https://doi.org/10.1039/C9NR03162F
Download PDF

  • Abstract

    High Resolution Image
    Download MS PowerPoint Slide

    Figure 1

    Figure 1. Schematic of two-step gold nanoparticle (AuNP) preparation consisting of AuNP synthesis with oleylamine (OAm) and subsequent functionalization via thiol-for-OAm ligand exchange.

    High Resolution Image
    Download MS PowerPoint Slide

    Figure 2

    Figure 2. Oleylamine-based synthesis of gold nanoparticles. (a) Representative TEM images for different reaction temperatures. (b) Average size and standard deviation of the nanoparticle populations as a function of reaction temperature.

    High Resolution Image
    Download MS PowerPoint Slide

    Figure 3

    Figure 3. Thiol-for-OAm ligand exchange for homoligand AuNPs. NMR and TGA results for AuNPs before and after thiol-for-OAm ligand exchange using MUS, OT, and MUO, respectively. The 1H NMR spectra of various AuNPs were obtained after purification and subsequent I2-induced ligand desorption.

    High Resolution Image
    Download MS PowerPoint Slide

    Figure 4

    Figure 4. Variation of ligand composition for mixed ligand MUS-OT AuNPs through the feed ratio. (a) Chemical shift profile after purification and subsequent I2-induced ligand desorption and (b) the calculated ligand yield ratio with respect to the ligand feed ratio.

    High Resolution Image
    Download MS PowerPoint Slide

  • References

    ARTICLE SECTIONS
    Jump To

    This article references 62 other publications.

    1. 1
      Barnes, W. L.; Dereux, A.; Ebbesen, T. W. Surface Plasmon Subwavelength Optics. Nature 2003, 424, 824– 830,  DOI: 10.1038/nature01937
      1
      Surface plasmon subwavelength optics
      Barnes, William L.; Dereux, Alain; Ebbesen, Thomas W.
      Nature (London, United Kingdom) (2003), 424 (6950), 824-830CODEN: NATUAS; ISSN:0028-0836. (Nature Publishing Group)
      A review. Surface plasmons are waves that propagate along the surface of a conductor. By altering the structure of a metal's surface, the properties of surface plasmons - in particular their interaction with light - can be tailored, which offers the potential for developing new types of photonic device. This could lead to miniaturized photonic circuits with length scales that are much smaller than those currently achieved. Surface plasmons are being explored for their potential in subwavelength optics, data storage, light generation, microscopy and bio-photonics.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXmt1ant7g%253D&md5=f34c9c0ea2de46f7b70d9b8aa552a459
    2. 2
      Tian, Y.; Tatsuma, T. Mechanisms and Applications of Plasmon-Induced Charge Separation at TiO2 Films Loaded with Gold Nanoparticles. J. Am. Chem. Soc. 2005, 127, 7632– 7637,  DOI: 10.1021/ja042192u
      2
      Mechanisms and Applications of Plasmon-Induced Charge Separation at TiO2 Films Loaded with Gold Nanoparticles
      Tian, Yang; Tatsuma, Tetsu
      Journal of the American Chemical Society (2005), 127 (20), 7632-7637CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      Plasmon-induced photoelectrochem. in the visible region was studied for Au nanoparticle-nanoporous TiO2 composites (Au-TiO2) prepd. by photocatalytic deposition of Au in a porous TiO2 film. Photo-action spectra for open-circuit potential and short-circuit current agreed with the absorption spectrum of Au nanoparticles in the TiO2 film. The Au nanoparticles are photoexcited due to plasmon resonance and charge sepn. is accomplished by the transfer of photoexcited electrons from the Au particle to the TiO2 conduction band with the simultaneous transfer of compensating electrons from a donor in the soln. to the Au particles. In addn. to its low cost and ease of prepn., a photovoltaic cell with the optimized electron mediator, Fe2+/3+, exhibits an optimum incident photon to current conversion efficiency (IPCE) of 26%. The Au-TiO2 can photo-catalytically oxidize EtOH and MeOH at the expense of O redn. under visible light, it is potentially applicable to a new class of photocatalysts and photovoltaic fuel cells.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXjslKqtrw%253D&md5=77c3140900eca9cdbae5bc11ad521ccc
    3. 3
      Haruta, M.; Yamada, N.; Kobayashi, T.; Iijima, S. Gold Catalysts Prepared by Coprecipitation for Low-Temperature Oxidation of Hydrogen and of Carbon Monoxide. J. Catal. 1989, 115, 301– 309,  DOI: 10.1016/0021-9517(89)90034-1
      3
      Gold catalysts prepared by coprecipitation for low-temperature oxidation of hydrogen and of carbon monoxide
      Haruta, M.; Yamada, N.; Kobayashi, T.; Iijima, S.
      Journal of Catalysis (1989), 115 (2), 301-9CODEN: JCTLA5; ISSN:0021-9517.
      Novel Au catalysts were prepd. by copptn. from an aq. soln. of HAuCl4 and the nitrates of various transition metals. Calcination of the coppts. in air at 400° produced ultrafine Au particles <10 nm which were uniformly dispersed on the transition metal oxides. Among them, Au/α-Fe2O3, Au/Co3O4, and Au/NiO were highly active for H2 and CO oxidn., showing markedly enhanced catalytic activities due to the combined effect of Au and the transition metal oxides. For the oxidn. of CO they were active even at a temp. as low as -70°.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaL1MXhtVamsbY%253D&md5=e5251756c7ba5548ab855a97d979cce4
    4. 4
      Corma, A.; Garcia, H. Supported Gold Nanoparticles as Catalysts for Organic Reactions. Chem. Soc. Rev. 2008, 37, 2096– 2126,  DOI: 10.1039/b707314n
      4
      Supported gold nanoparticles as catalysts for organic reactions
      Corma, Avelino; Garcia, Hermenegildo
      Chemical Society Reviews (2008), 37 (9), 2096-2126CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
      A review. This crit. review is intended to attract the interest of org. chemists and researchers on green and sustainable chem. on the catalytic activity of supported gold nanoparticles in org. transformations. In the general part of this crit. review, emphasis is given to the different procedures to form supported gold nanoparticles and to the importance of the support cooperating in the catalysis. Also the convergence of homogeneous and heterogeneous catalysis in the study of gold nanoparticles has been discussed. The core part of this review is constituted by sections in which the reactions catalyzed by supported gold nanoparticles are described. Special emphasis is made on the unique ability of gold catalysts to promote addns. to multiple C-C bonds, benzannulations, and alc. oxidn. by oxygen.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtVOitbzN&md5=0ced6d30cce14be1fc0f5b295bc610fc
    5. 5
      Wang, C.; Yin, H.; Dai, S.; Sun, S. A General Approach to Noble Metal-Metal Oxide Dumbbell Nanoparticles and Their Catalytic Application for CO Oxidation. Chem. Mater. 2010, 22, 3277– 3282,  DOI: 10.1021/cm100603r
      5
      A General Approach to Noble Metal-Metal Oxide Dumbbell Nanoparticles and Their Catalytic Application for CO Oxidation
      Wang, Chao; Yin, Hongfeng; Dai, Sheng; Sun, Shouheng
      Chemistry of Materials (2010), 22 (10), 3277-3282CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)
      Heterogeneous, dumbbell-like nanoparticles represent an important type of composite nano-material which attracts growing interest. A general approach to noble metal/metal oxide dumbbell nanoparticles based on seed-mediated growth is reported. Metal oxides are grown over pre-synthesized noble metal seeds by thermal decompn. of metal carbonyl followed by oxidn. in air. As-synthesized dumbbell nanoparticles have intrinsic epitaxial links between the metal and oxide, providing enhanced hetero-junction interactions. The properties of one component are readily modified by the other in these nanoparticles, as demonstrated by the enhanced catalytic activity toward CO oxidn. of such dumbbell nanoparticles vs. their counterparts synthesized by conversional methods. Thus, the hetero-junction effects provided in such nano-structures offer another degree of freedom to tailor material properties. The developed synthetic strategy could also be generalized to other systems and therefore represent a general approach to heterogeneous nano-materials for functional applications.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXltFyksbo%253D&md5=1bf31952c58093912137f537cfef9315
    6. 6
      Howes, P. D.; Chandrawati, R.; Stevens, M. M. Colloidal Nanoparticles as Advanced Biological Sensors. Science 2014, 346, 1247390,  DOI: 10.1126/science.1247390
      6
      Bionanotechnology. Colloidal nanoparticles as advanced biological sensors
      Howes Philip D; Chandrawati Rona; Stevens Molly M
      Science (New York, N.Y.) (2014), 346 (6205), 1247390 ISSN:.
      Colloidal nanoparticle biosensors have received intense scientific attention and offer promising applications in both research and medicine. We review the state of the art in nanoparticle development, surface chemistry, and biosensing mechanisms, discussing how a range of technologies are contributing toward commercial and clinical translation. Recent examples of success include the ultrasensitive detection of cancer biomarkers in human serum and in vivo sensing of methyl mercury. We identify five key materials challenges, including the development of robust mass-scale nanoparticle synthesis methods, and five broader challenges, including the use of simulations and bioinformatics-driven experimental approaches for predictive modeling of biosensor performance. The resultant generation of nanoparticle biosensors will form the basis of high-performance analytical assays, effective multiplexed intracellular sensors, and sophisticated in vivo probes.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2M7ntVKhug%253D%253D&md5=25ce494a8bbfe4fd7d73818b3267d674
    7. 7
      Dykman, L.; Khlebtsov, N. Gold Nanoparticles in Biomedical Applications: Recent Advances and Perspectives. Chem. Soc. Rev. 2012, 41, 2256– 2282,  DOI: 10.1039/C1CS15166E
      7
      Gold nanoparticles in biomedical applications: recent advances and perspectives
      Dykman, Lev; Khlebtsov, Nikolai
      Chemical Society Reviews (2012), 41 (6), 2256-2282CODEN: CSRVBR; ISSN:0306-0012. (Royal Society of Chemistry)
      A review. Gold nanoparticles (GNPs) with controlled geometrical, optical, and surface chem. properties are the subject of intensive studies and applications in biol. and medicine. To date, the ever increasing diversity of published examples has included genomics and biosensorics, immunoassays and clin. chem., photothermolysis of cancer cells and tumors, targeted delivery of drugs and antigens, and optical bioimaging of cells and tissues with state-of-the-art nanophotonic detection systems. This crit. review is focused on the application of GNP conjugates to biomedical diagnostics and analytics, photothermal and photodynamic therapies, and delivery of target mols. Distinct from other published reviews, we present a summary of the immunol. properties of GNPs. For each of the above topics, the basic principles, recent advances, and current challenges are discussed (508 refs.).
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XivFWlsbc%253D&md5=b08dfe416c306e5f35a69d0df15bf37d
    8. 8
      Shukla, R.; Bansal, V.; Chaudhary, M.; Basu, A.; Bhonde, R. R.; Sastry, M. Biocompatibility of Gold Nanoparticles and Their Endocytotic Fate inside the Cellular Compartment: a Microscopic Overview. Langmuir 2005, 21, 10644– 10654,  DOI: 10.1021/la0513712
      8
      Biocompatibility of Gold Nanoparticles and Their Endocytotic Fate Inside the Cellular Compartment: A Microscopic Overview
      Shukla, Ravi; Bansal, Vipul; Chaudhary, Minakshi; Basu, Atanu; Bhonde, Ramesh R.; Sastry, Murali
      Langmuir (2005), 21 (23), 10644-10654CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
      Macrophages are one of the principal immune effector cells that play essential roles as secretory, phagocytic, and antigen-presenting cells in the immune system. In this study, we address the issue of cytotoxicity and immunogenic effects of gold nanoparticles on RAW264.7 macrophage cells. The cytotoxicity of gold nanoparticles has been correlated with a detailed study of their endocytic uptake using various microscopy tools such as at. force microscopy (AFM), confocal-laser-scanning microscopy (CFLSM), and TEM. Our findings suggest that Au(0) nanoparticles are not cytotoxic, reduce the prodn. of reactive oxygen and nitrite species, and do not elicit secretion of proinflammatory cytokines TNF-α and IL1-β, making them suitable candidates for nanomedicine. AFM measurements suggest that gold nanoparticles are internalized inside the cell via a mechanism involving pinocytosis, while CFLSM and TEM studies indicate their internalization in lysosomal bodies arranged in perinuclear fashion. Our studies thus underline the noncytotoxic, nonimmunogenic, and biocompatible properties of gold nanoparticles with the potential for application in nanoimmunol., nanomedicine, and nanobiotechnol.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXhtVegt7fM&md5=ea38d76c875da8c93d0e3258f4ae15cf
    9. 9
      Kinnear, C.; Moore, T. L.; Rodriguez-Lorenzo, L.; Rothen-Rutishauser, B.; Petri-Fink, A. Form Follows Function: Nanoparticle Shape and Its Implications for Nanomedicine. Chem. Rev. 2017, 117, 11476– 11521,  DOI: 10.1021/acs.chemrev.7b00194
      9
      Form Follows Function: Nanoparticle Shape and Its Implications for Nanomedicine
      Kinnear, Calum; Moore, Thomas L.; Rodriguez-Lorenzo, Laura; Rothen-Rutishauser, Barbara; Petri-Fink, Alke
      Chemical Reviews (Washington, DC, United States) (2017), 117 (17), 11476-11521CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)
      A review. This review is a comprehensive description of the past decade of research into understanding how the geometry and size of nanoparticles affects their interaction with biol. systems: from single cells to whole organisms. Recently, there has been a great deal of effort to use both the shape and size of nanoparticles to target specific cellular uptake mechanisms, biodistribution patterns, and pharmacokinetics. While the successes of spherical lipid-based nanoparticles have heralded marked changes in chemotherapy worldwide, the history of asbestos-induced lung disease casts a long shadow over fibrous materials to date. The impact of particle morphol. is known to be intertwined with many physicochem. parameters, namely size, elasticity, surface chem., and biopersistence. In this review, we first highlight some of the morphologies obsd. in nature, as well as shapes available to us through synthetic strategies. Following this, we discuss attempts to understand the cellular uptake of nanoparticles through various theor. models before comparing this with observations from in vitro and in vivo expts. In addn., we consider the impact of nanoparticle shape at different size regimes on targeting, cytotoxicity, and cellular mechanics.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsVWgt7rF&md5=0c21904caafe4912ff0604dc9a8335df
    10. 10
      Castner, D. G.; Hinds, K.; Grainger, D. W. X-ray Photoelectron Spectroscopy Sulfur 2p Study of Organic Thiol and Disulfide Binding Interactions with Gold Surfaces. Langmuir 1996, 12, 5083– 5086,  DOI: 10.1021/la960465w
      10
      X-ray Photoelectron Spectroscopy Sulfur 2p Study of Organic Thiol and Disulfide Binding Interactions with Gold Surfaces
      Castner, David G.; Hinds, Kenneth; Grainger, David W.
      Langmuir (1996), 12 (21), 5083-5086CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
      The presence of 2 S species was detected in XPS studies of thiol and disulfide mols. adsorbed on Au surfaces. These species are assigned to bound thiolate (S2p3/2 binding energy 162 eV) and unbound thiol/disulfide (S2p3/2 binding energy from 163.5 to 164 eV). These assignments are consistent with XPS data obtained from different thiols (C12, C16, C18, and C22 alkane thiols, a fluorinated thiol, and a cyclic siloxanethiol) and different adsorption conditions (solvent type, thiol concn., temp., and rinsing). In particular, the use of a poor solvent for thiol adsorption solns. (e.g., EtOH for long chain alkanethiols) and the lack of a rinsing step both resulted in unbound thiol mols. present at the surface of the bound thiolate monolayer. This has implications for recent studies asserting the presence of multiple binding sites for Au-thiolate species in org. monolayers.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XlvVSgsrg%253D&md5=d5ffa08fd03bf884fa661179edd0de3d
    11. 11
      Bürgi, T. Properties of the Gold-Sulphur Interface: from Self-Assembled Monolayers to Clusters. Nanoscale 2015, 7, 15553– 15567,  DOI: 10.1039/C5NR03497C
      11
      Properties of the gold-sulphur interface: from self-assembled monolayers to clusters
      Burgi, Thomas
      Nanoscale (2015), 7 (38), 15553-15567CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)
      The gold-sulfur interface of self-assembled monolayers (SAMs) was extensively studied some time ago. More recently tremendous progress has been made in the prepn. and characterization of thiolate-protected gold clusters. In this feature article we address different properties of the two systems such as their structure, the mobility of the thiolates on the surface and other dynamical aspects, the chirality of the structures and characteristics related to it and their vibrational properties. SAMs and clusters are in the focus of different communities that typically use different exptl. approaches to study the resp. systems. However, it seems that the nature of the Au-S interfaces in the two cases is quite similar. Recent single crystal X-ray structures of thiolate-protected gold clusters reveal staple motifs characterized by gold ad-atoms sandwiched between two sulfur atoms. In any case, more and more studies highlight the dynamic nature of the Au-S interface, both on flat surfaces and in clusters. At temps. slightly above ambient thiolates migrate on the gold surface and on clusters. Evidence for desorption of thiolates at room temp., at least under certain conditions, has been demonstrated for both systems. The adsorbed thiolate can lead to chirality at different lengths scales, which has been shown both on surfaces and for clusters. Chirality can also be transferred from a chiral surface to an adsorbate, as evidenced by vibrational spectroscopy.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhsVGju7rE&md5=bc7e3fe58112c953fcb9b52bbb2d4b54
    12. 12
      Giljohann, D. A.; Seferos, D. S.; Daniel, W. L.; Massich, M. D.; Patel, P. C.; Mirkin, C. A. Gold Nanoparticles for Biology and Medicine. Angew. Chem., Int. Ed. 2010, 49, 3280– 3294,  DOI: 10.1002/anie.200904359
      12
      Gold Nanoparticles for Biology and Medicine
      Giljohann, David A.; Seferos, Dwight S.; Daniel, Weston L.; Massich, Matthew D.; Patel, Pinal C.; Mirkin, Chad A.
      Angewandte Chemie, International Edition (2010), 49 (19), 3280-3294CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
      A review. Gold colloids have fascinated scientists for over a century and are now heavily utilized in chem., biol., engineering, and medicine. Today these materials can be synthesized reproducibly, modified with seemingly limitless chem. functional groups, and, in certain cases, characterized with at.-level precision. This Review highlights recent advances in the synthesis, bioconjugation, and cellular uses of gold nanoconjugates. There are now many examples of highly sensitive and selective assays based upon gold nanoconjugates. In recent years, focus has turned to therapeutic possibilities for such materials. Structures which behave as gene-regulating agents, drug carriers, imaging agents, and photoresponsive therapeutics have been developed and studied in the context of cells and many debilitating diseases. These structures are not simply chosen as alternatives to mol.-based systems, but rather for their new phys. and chem. properties, which confer substantive advantages in cellular and medical applications.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXlt1GlsbY%253D&md5=0809d2a7d09124a8975d5ea77e679442
    13. 13
      Saha, K.; Agasti, S. S.; Kim, C.; Li, X.; Rotello, V. M. Gold Nanoparticles in Chemical and Biological Sensing. Chem. Rev. 2012, 112, 2739– 2779,  DOI: 10.1021/cr2001178
      13
      Gold nanoparticles in chemical and biological sensing
      Saha, Krishnendu; Agasti, Sarit S.; Kim, Chaekyu; Li, Xiaoning; Rotello, Vincent M.
      Chemical Reviews (Washington, DC, United States) (2012), 112 (5), 2739-2779CODEN: CHREAY; ISSN:0009-2665. (American Chemical Society)
      A review. Topics include synthesis ans surface functionalization; phys. properties; colorimetric and fluorimetric sensing; elec. al and electrochem. sensing; SERS; gold nanoparticles in quartz crystal microbalance-based sensing; application of gold nanoparticles in bio-barcode assays.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38Xhs1ehtL0%253D&md5=350c3c2eeab3d98ed42ffe88cf137c14
    14. 14
      Yeh, Y.-C.; Creran, B.; Rotello, V. M. Gold Nanoparticles: Preparation, Properties, and Applications in Bionanotechnology. Nanoscale 2012, 4, 1871– 1880,  DOI: 10.1039/C1NR11188D
      14
      Gold nanoparticles: preparation, properties, and applications in bionanotechnology
      Yeh, Yi-Cheun; Creran, Brian; Rotello, Vincent M.
      Nanoscale (2012), 4 (6), 1871-1880CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)
      A review. Gold nanoparticles (AuNPs) are important components for biomedical applications. AuNPs have been widely employed for diagnostics, and have seen increasing use in the area of therapeutics. In this mini-review, we present fabrication strategies for AuNPs and highlight a selection of recent applications of these materials in bionanotechnol.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XjtFyqsL4%253D&md5=324ab15e57fc9535c4180020852b374a
    15. 15
      Le Ouay, B.; Guldin, S.; Luo, Z.; Allegri, S.; Stellacci, F. Freestanding Ultrathin Nanoparticle Membranes Assembled at Transient Liquid-Liquid Interfaces. Adv. Mater. Interfaces 2016, 3, 1600191,  DOI: 10.1002/admi.201600191
      There is no corresponding record for this reference.
    16. 16
      DeVries, G. A.; Brunnbauer, M.; Hu, Y.; Jackson, A. M.; Long, B.; Neltner, B. T.; Uzun, O.; Wunsch, B. H.; Stellacci, F. Divalent Metal Nanoparticles. Science 2007, 315, 358– 361,  DOI: 10.1126/science.1133162
      16
      Divalent Metal Nanoparticles
      DeVries, Gretchen A.; Brunnbauer, Markus; Hu, Ying; Jackson, Alicia M.; Long, Brenda; Neltner, Brian T.; Uzun, Oktay; Wunsch, Benjamin H.; Stellacci, Francesco
      Science (Washington, DC, United States) (2007), 315 (5810), 358-361CODEN: SCIEAS; ISSN:0036-8075. (American Association for the Advancement of Science)
      Nanoparticles can be used as the building blocks for materials such as supracrystals or ionic liqs. However, they lack the ability to bond along specific directions as atoms and mols. do. We report a simple method to place target mols. specifically at two diametrically opposed positions in the mol. coating of metal nanoparticles. The approach is based on the functionalization of the polar singularities that must form when a curved surface is coated with ordered monolayers, such as a phase-sepd. mixt. of ligands. The mols. placed at these polar defects have been used as chem. handles to form nanoparticle chains that in turn can generate self-standing films.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXmt1Kgsg%253D%253D&md5=722ecd96276839ab19cbdccb3a1c2c34
    17. 17
      Kuna, J. J.; Voïtchovsky, K.; Singh, C.; Jiang, H.; Mwenifumbo, S.; Ghorai, P. K.; Stevens, M. M.; Glotzer, S. C.; Stellacci, F. The Effect of Nanometre-Scale Structure on Interfacial Energy. Nat. Mater. 2009, 8, 837– 842,  DOI: 10.1038/nmat2534
      17
      The effect of nanometre-scale structure on interfacial energy
      Kuna, Jeffrey J.; Voitchovsky, Kislon; Singh, Chetana; Jiang, Hao; Mwenifumbo, Steve; Ghorai, Pradip K.; Stevens, Molly M.; Glotzer, Sharon C.; Stellacci, Francesco
      Nature Materials (2009), 8 (10), 837-842CODEN: NMAACR; ISSN:1476-1122. (Nature Publishing Group)
      Natural surfaces are often structured with nanometer-scale domains, yet a framework providing a quant. understanding of how nanostructure affects interfacial energy, γSL, is lacking. Conventional continuum thermodn. treats γSL solely as a function of av. compn., ignoring structure. When a surface has domains commensurate in size with solvent mols., γSL is detd. not only by its av. compn. but also by a structural component that causes γSL to deviate from the continuum prediction by a substantial amt., ≤20% in the system. By contrasting surfaces coated with either mol.- ( < 2 nm) or larger-scale domains ( > 5 nm), whereas the latter surfaces have the expected linear dependence of γSL on surface compn., the former show a markedly different nonmonotonic trend. Mol. dynamics simulations show how the organization of the solvent mols. at the interface is controlled by the nanostructured surface, which in turn appreciably modifies γSL.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtFKns7rO&md5=d99bf092f66293176d2f9caa62a08634
    18. 18
      Colangelo, E.; Comenge, J.; Paramelle, D.; Volk, M.; Chen, Q.; Lévy, R. Characterizing Self-Assembled Monolayers on Gold Nanoparticles. Bioconjugate Chem. 2017, 28, 11– 22,  DOI: 10.1021/acs.bioconjchem.6b00587
      18
      Characterizing Self-Assembled Monolayers on Gold Nanoparticles
      Colangelo, Elena; Comenge, Joan; Paramelle, David; Volk, Martin; Chen, Qiubo; Levy, Raphael
      Bioconjugate Chemistry (2017), 28 (1), 11-22CODEN: BCCHES; ISSN:1043-1802. (American Chemical Society)
      A review. A key aspect of nanoscience is to control the assembly of complex materials from a "bottom-up" approach. The self-assembly and self-organization of small ligands at the surface of nanoparticles represent a possible starting route for the prepn. of (bio)nanomaterials with precise (bio)phys. and (bio)chem. properties. However, surface characterization and elucidation of the structure-properties relation, essentials to envision such control, remain challenging and are often poorly studied. This Topical Review aims to discuss different levels of surface characterization, giving an overview of the exptl. and computational approaches that were used to provide insights into the self-assembled monolayer with mol. details. The methods and strategies discussed focus on the characterization of self-assembled monolayers at the gold nanoparticle surface, but most of them could also be applied to other types of nanoparticles.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhvVGgsLnO&md5=c9446bb052f314b3720360d65551fe1b
    19. 19
      Bradford, S. M.; Fisher, E. A.; Meli, M.-V. Ligand Shell Composition-Dependent Effects on the Apparent Hydrophobicity and Film Behavior of Gold Nanoparticles at the Air-Water Interface. Langmuir 2016, 32, 9790– 9796,  DOI: 10.1021/acs.langmuir.6b02238
      19
      Ligand Shell Composition-Dependent Effects on the Apparent Hydrophobicity and Film Behavior of Gold Nanoparticles at the Air-Water Interface
      Bradford, Stephen M.; Fisher, Elizabeth A.; Meli, M.-Vicki
      Langmuir (2016), 32 (38), 9790-9796CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
      Nanoparticles with well-defined interfacial energy and wetting properties are needed for a broad range of applications involving nanoparticle self-assembly including the formation of superlattices, stability of Pickering emulsions, and for the control of nanoparticle interactions with biol. membranes. Theor., simulated, and recent exptl. studies have found nanometer-scale chem. heterogeneity to have important effects on hydrophobic interactions. Here we report the study of 4 nm gold nanoparticles with compositionally well-defined mixed ligand shells of hydroxyl-(OH) and methyl-(CH3) terminated alkylthiols as Langmuir films. Compns. ranging from 0-25% hydroxyl were examd. and reveal nonmonotonic changes in particle hydrophobicity at the air-water interface. Unlike nanoparticles capped exclusively with a methyl-terminated alkylthiol, extensive particle aggregation is found for ligand shells contg. <2% hydroxyl-terminated chains. This aggregation was lessened upon increasing the quantity of OH-terminated chains. Nanoparticles capped with 25% OH yield films of well-sepd. nanoparticles exhibiting a fluid-phase regime in the surface pressure vs area isotherm. Compression-expansion hysteresis, monolayer collapse, and mean nanoparticle area measurements support the TEM-obsd. changes in film morphol. Such clear changes in the hydrophobicity of nanoparticles based on very small changes in the ligand shell compn. are shown to impact the process of interfacial nanoparticle self-assembly and are an important demonstration of nanoscale wetting with consequences in both materials and biol. applications of nanoparticles that require tunable hydrophobicity.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC28XhsVKrtLbP&md5=a3a7ba1ff2c734f15933f7c2164fb2dc
    20. 20
      Edwards, W.; Marro, N.; Turner, G.; Kay, E. R. Continuum Tuning of Nanoparticle Interfacial Properties by Dynamic Covalent Exchange. Chem. Sci. 2018, 9, 125– 133,  DOI: 10.1039/C7SC03666C
      20
      Continuum tuning of nanoparticle interfacial properties by dynamic covalent exchange
      Edwards, William; Marro, Nicolas; Turner, Grace; Kay, Euan R.
      Chemical Science (2018), 9 (1), 125-133CODEN: CSHCCN; ISSN:2041-6520. (Royal Society of Chemistry)
      Surface chem. compn. is fundamental to detg. properties on the nanoscale, making precise control over surface chem. crit. to being able to optimize nanomaterials for virtually any application. Surface-engineering independent of the prepn. of the underlying nanomaterial is particularly attractive for efficient, divergent synthetic strategies, and for the potential to create reactive, responsive and smart nanodevices. For monolayer-stabilized nanoparticles, established methods include ligand exchange to replace the ligand shell in its entirety, encapsulation with amphiphilic (macro)mols., noncovalent interactions with surface-bound biomols., or a relatively limited no. of covalent bond forming reactions. Yet, each of these approaches has considerable drawbacks. Here we show that dynamic covalent exchange at the periphery of the nanoparticle-stabilizing monolayer allows surface-bound ligand mol. structure to be substantially modified in mild and reversible processes that are independent of the nanoparticle-mol. interface. Simple stoichiometric variation allows the extent of exchange to be controlled, generating a range of kinetically stable mixed-monolayer compns. across an otherwise identical, self-consistent series of nanoparticles. This approach can be used to modulate nanoparticle properties that are defined by the monolayer compn. We demonstrate switching of nanoparticle solvent compatibility between widely differing solvents - spanning hexane to water - and the ability to tune soly. across the entire continuum between these extremes, all from a single nanoparticle starting point. We also demonstrate that fine control over mixed-monolayer compn. influences the assembly of discrete, colloidally stable nanoparticle clusters. By carefully assessing monolayer compn. in each state, using both in situ and ex situ methods, we are able to correlate the mol.-level details of the nanoparticle-bound monolayer with system-level properties and behavior. These empirically detd. relationships contribute fundamental insights on nanoscale structure-function relationships, which are currently beyond the capabilities of ab initio prediction.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhvVartLrK&md5=ae50291b8d189e5f4e5835cd0f725c54
    21. 21
      Jiang, Y.; Huo, S.; Mizuhara, T.; Das, R.; Lee, Y.-W.; Hou, S.; Moyano, D. F.; Duncan, B.; Liang, X.-J.; Rotello, V. M. The Interplay of Size and Surface Functionality on the Cellular Uptake of Sub-10 nm Gold Nanoparticles. ACS Nano 2015, 9, 9986– 9993,  DOI: 10.1021/acsnano.5b03521
      21
      The Interplay of Size and Surface Functionality on the Cellular Uptake of Sub-10 nm Gold Nanoparticles
      Jiang, Ying; Huo, Shuaidong; Mizuhara, Tsukasa; Das, Riddha; Lee, Yi-Wei; Hou, Singyuk; Moyano, Daniel F.; Duncan, Bradley; Liang, Xing-Jie; Rotello, Vincent M.
      ACS Nano (2015), 9 (10), 9986-9993CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)
      Correlation of the surface physicochem. properties of nanoparticles with their interactions with biosystems provides key foundational data for nanomedicine. We report here the systematic synthesis of 2, 4, and 6 nm core gold nanoparticles (AuNP) featuring neutral (zwitterionic), anionic, and cationic headgroups. The cellular internalization of these AuNPs was quantified, providing a parametric evaluation of charge and size effects. Contrasting behavior was obsd. with these systems: with zwitterionic and anionic particles, uptake decreased with increasing AuNP size, whereas with cationic particles, uptake increased with increasing particle size. Through mechanistic studies of the uptake process, we can attribute these opposing trends to a surface-dictated shift in uptake pathways. Zwitterionic NPs are primarily internalized through passive diffusion, while the internalization of cationic and anionic NPs is dominated by multiple endocytic pathways. Our study demonstrates that size and surface charge interact in an interrelated fashion to modulate nanoparticle uptake into cells, providing an engineering tool for designing nanomaterials for specific biol. applications.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXhs1SisL3J&md5=acb35b2734a4c7ad78d5d26d7a3c22f1
    22. 22
      Hung, A.; Mwenifumbo, S.; Mager, M.; Kuna, J. J.; Stellacci, F.; Yarovsky, I.; Stevens, M. M. Ordering Surfaces on the Nanoscale: Implications for Protein Adsorption. J. Am. Chem. Soc. 2011, 133, 1438– 1450,  DOI: 10.1021/ja108285u
      22
      Ordering Surfaces on the Nanoscale: Implications for Protein Adsorption
      Hung, Andrew; Mwenifumbo, Steve; Mager, Morgan; Kuna, Jeffrey J.; Stellacci, Francesco; Yarovsky, Irene; Stevens, Molly M.
      Journal of the American Chemical Society (2011), 133 (5), 1438-1450CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      Monolayer-protected metal nanoparticles (MPMNs) are a newly discovered class of nanoparticles with an ordered, striped domain structure that can be readily manipulated by altering the ratio of the hydrophobic to hydrophilic ligands. This property makes them uniquely suited to systematic studies of the role of nanostructuring on biomol. adsorption, a phenomenon of paramount importance in biomaterials design. In this work, the authors examine the interaction of the simple, globular protein cytochrome C (Cyt C) with MPMN surfaces using exptl. protein assays and computational mol. dynamics simulations. Exptl. assays revealed that adsorption of Cyt C generally increased with increasing surface polar ligand content, indicative of the dominance of hydrophilic interactions in Cyt C-MPMN binding. Protein-surface adsorption enthalpies calcd. from computational simulations employing rigid-backbone coarse-grained Cyt C and MPMN models indicate a monotonic increase in adsorption enthalpy with respect to MPMN surface polarity. These results are in qual. agreement with exptl. results and suggest that Cyt C does not undergo significant structural disruption upon adsorption to MPMN surfaces. Coarse-grained and atomistic simulations furthermore elucidated the important role of lysine in facilitating Cyt C adsorption to MPMN surfaces. The amphipathic character of the lysine side chain enables it to form close contacts with both polar and nonpolar surface ligands simultaneously, rendering it esp. important for interactions with surfaces composed of adjacent nanoscale chem. domains. The importance of these structural characteristics of lysine suggests that proteins may be engineered to specifically interact with nanomaterials by targeted incorporation of unnatural amino acids possessing dual affinity to differing chem. motifs.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXit1Cgtw%253D%253D&md5=92eb8b626057474e80f31812c79a7844
    23. 23
      Huang, R.; Carney, R. P.; Stellacci, F.; Lau, B. L. Protein-Nanoparticle Interactions: the Effects of Surface Compositional and Structural Heterogeneity Are Scale Dependent. Nanoscale 2013, 5, 6928– 6935,  DOI: 10.1039/c3nr02117c
      23
      Protein-nanoparticle interactions: the effects of surface compositional and structural heterogeneity are scale dependent
      Huang, Rixiang; Carney, Randy P.; Stellacci, Francesco; Lau, Boris L. T.
      Nanoscale (2013), 5 (15), 6928-6935CODEN: NANOHL; ISSN:2040-3372. (Royal Society of Chemistry)
      Nanoparticles (NPs) in the biol. environment are exposed to a large variety and concn. of proteins. Proteins are known to adsorb in a corona' like structure on the surface of NPs. In this study, we focus on the effects of surface compositional and structural heterogeneity on protein adsorption by examg. the interaction of self-assembled monolayer coated gold NPs (AuNPs) with two types of proteins: ubiquitin and fibrinogen. This work was designed to systematically investigate the role of surface heterogeneity in nanoparticle-protein interaction. We have chosen the particles as well as the proteins to provide different types (in distribution and length-scale) of heterogeneity. The goal was to unveil the role of heterogeneity and of its length-scale in the particle-protein interaction. Dynamic light scattering and CD spectroscopy were used to reveal different interactions at pH above and below the isoelec. points of the proteins, which is related to the charge heterogeneity on the protein surface. At pH 7.4, there was only a monolayer of proteins adsorbed onto the NPs and the secondary structure of proteins remained intact. At pH 4.0, large aggregates of nanoparticle-protein complexes were formed and the secondary structures of the proteins were significantly disrupted. In terms of interaction thermodn., results from isothermal titrn. calorimetry showed that ubiquitin adsorbed differently onto (1) AuNPs with charged and nonpolar terminals organized into nano-scale structure (66-34 OT), (2) AuNPs with randomly distributed terminals (66-34 brOT), and (3) AuNPs with homogeneously charged terminals (MUS). This difference in adsorption behavior was not obsd. when AuNPs interacted with fibrinogen. The results suggested that the interaction between the proteins and AuNPs was influenced by the surface heterogeneity on the AuNPs, and this influence depends on the scale of surface heterogeneity and the size of the proteins.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXhtV2ku7zM&md5=7fb21e3661ff44125adede59cdc0dc19
    24. 24
      Brust, M.; Fink, J.; Bethell, D.; Schiffrin, D.; Kiely, C. Synthesis and Reactions of Functionalised Gold Nanoparticles. J. Chem. Soc., Chem. Commun. 1995, 1655– 1656,  DOI: 10.1039/c39950001655
      24
      Synthesis and reactions of functionalized gold nanoparticles
      Brust, M.; Fink, J.; Bethell, D.; Schiffrin, D. J.; Kiely, C.
      Journal of the Chemical Society, Chemical Communications (1995), (16), 1655-6CODEN: JCCCAT; ISSN:0022-4936. (Royal Society of Chemistry)
      Stable functionalized Au nanoparticles were prepd. by simultaneous redn. of tetrachloroaurate ions and attachment of p-mercaptophenol to the growing Au nuclei. This gave a material characterized by esterification of the vacant functionality of the bifunctional thiol ligand.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK2MXns1yksrs%253D&md5=5db08af7554698de25477eccbb226449
    25. 25
      Zheng, N.; Fan, J.; Stucky, G. D. One-Step One-Phase Synthesis of Monodisperse Noble-Metallic Nanoparticles and Their Colloidal Crystals. J. Am. Chem. Soc. 2006, 128, 6550– 6551,  DOI: 10.1021/ja0604717
      25
      One-Step One-Phase Synthesis of Monodisperse Noble-Metallic Nanoparticles and Their Colloidal Crystals
      Zheng, Nanfeng; Fan, Jie; Stucky, Galen D.
      Journal of the American Chemical Society (2006), 128 (20), 6550-6551CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      A variety of metallic nanoparticles with a narrow size distribution have been synthesized in a facile one-phase method in which amine-borane complexes are applied as reducing agents. It is particularly striking that large colloidal crystals with sizes up to tens of micrometers can directly form from the reaction mixts. without any further treatment. By using the synthetic route described, large-scale syntheses of both mono- and alloyed metallic nanoparticles with a narrow size distribution can be easily achieved.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XjvFyitLw%253D&md5=2cc5c1e96c797aec50ef2a1db97902ee
    26. 26
      Wu, B.-H.; Yang, H.-Y.; Huang, H.-Q.; Chen, G.-X.; Zheng, N.-F. Solvent Effect on the Synthesis of Monodisperse Amine-Capped Au Nanoparticles. Chin. Chem. Lett. 2013, 24, 457– 462,  DOI: 10.1016/j.cclet.2013.03.054
      26
      Solvent effect on the synthesis of monodisperse amine-capped Au nanoparticles
      Wu, Bing-Hui; Yang, Hua-Yan; Huang, Hua-Qi; Chen, Guang-Xu; Zheng, Nan-Feng
      Chinese Chemical Letters (2013), 24 (6), 457-462CODEN: CCLEE7; ISSN:1001-8417. (Elsevier B.V.)
      A remarkable solvent effect in a single-phase synthesis of monodisperse amine-capped Au nanoparticles is demonstrated. Oleylamine-capped Au nanoparticles were prepd. via the redn. of HAuCl4 by an amine-borane complex in the presence of oleylamine in an org. solvent. When linear or planar hydrocarbon (e.g., n-hexane, n-octane, 1-octadecylene, benzene, and toluene) was used as the solvent, high-quality monodisperse Au nanoparticles with tunable sizes were obtained. However, Au nanoparticles with poor size dispersity were obtained when tetralin, chloroform or cyclohexane was used as the solvent. The revealed solvent effect allows the controlled synthesis of monodisperse Au nanoparticles with tunable size of 3-10 nm.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXmvV2ltr8%253D&md5=e1fbdc14a226bdaae0c5d6e7c4113429
    27. 27
      Shon, Y.-S.; Choo, H. Organic Reactions of Monolayer-Protected Metal Nanoparticles. C. R. Chim. 2003, 6, 1009– 1018,  DOI: 10.1016/j.crci.2003.08.008
      27
      Organic reactions of monolayer-protected metal nanoparticles
      Shon, Young-Seok; Choo, Hosun
      Comptes Rendus Chimie (2003), 6 (8-10), 1009-1018CODEN: CRCOCR; ISSN:1631-0748. (Editions Scientifiques et Medicales Elsevier)
      A review. This paper presents a concise review of various org. reactions of monolayer-protected metal nanoparticles, with an emphasis on their current applications. Org. reactions of monolayer-protected nanoparticles lead to the functionalized nanoparticles, which exhibit interesting properties such as catalytic, electrochem., photoresponsive, chem. sensing, and biocompatible properties.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXoslOgt7w%253D&md5=fd7ee7a2234cca45699fe8dafeee58b1
    28. 28
      Neouze, M.-A.; Schubert, U. Surface Modification and Functionalization of Metal and Metal Oxide Nanoparticles by Organic Ligands. Monatsh. Chem. 2008, 139, 183– 195,  DOI: 10.1007/s00706-007-0775-2
      28
      Surface Modification and Functionalization of Metal and Metal Oxide Nanoparticles by Organic Ligands
      Neouze, Marie-Alexandra; Schubert, Ulrich
      Monatshefte fuer Chemie (2008), 139 (3), 183-195CODEN: MOCMB7; ISSN:0026-9247. (Springer Wien)
      A review. Metal or metal oxide nanoparticles possess unique features compared to equiv. larger-scale materials. For applications, it is often necessary to stabilize or functionalize such nanoparticles. Thus, modification of the surface of nanoparticles is an important chem. challenge. In this survey, various possibilities are discussed how nanoparticles can be protected by org. ligands and how these ligands can be used to introduce functionalities. The preparative possibilities include grafting of an already functionalized ligand on the nanoparticle surface, exchanging part or all existing ligands on the nanoparticle surface, or grafting of a ligand on a nanoparticle followed by modification by org. chem. reactions.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXitlamt7o%253D&md5=c87c1fbd172cf021b9ba3862e48ca16b
    29. 29
      Hostetler, M. J.; Green, S. J.; Stokes, J. J.; Murray, R. W. Monolayers in Three Dimensions: Synthesis and Electrochemistry of ω-Functionalized Alkanethiolate-Stabilized Gold Cluster Compounds. J. Am. Chem. Soc. 1996, 118, 4212– 4213,  DOI: 10.1021/ja960198g
      29
      Monolayers in three dimensions: synthesis and electrochemistry of ω-functionalized alkanethiolate-stabilized gold cluster compounds
      Hostetler, Michael J.; Green, Stephen J.; Stokes, Jennifer J.; Murray, Royce W.
      Journal of the American Chemical Society (1996), 118 (17), 4212-13CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      The synthesis and characterization of Au cluster compds. contg. a mixt. of alkanethiolate and ω-substituted alkanethiolate ligands are reported. Cluster mols. prepd. with alkanethiolate ligands, according to previous work, have a ∼1.2 nm radius Au core that, modeled as a 309-Au atom cubooctahedron, bears a monolayer ligand skin of ∼95 alkenethiolate chains. The ω-functionalized clusters are synthesized by place exchange reactions in soln. mixts. of alkanethiolate cluster mols. and ω-substituted alkanethiols, where the ω-substituent can be -Br, -CN, vinyl, or ferrocenyl. The reaction products, according to 1H NMR spectroscopy, include cluster mols. with as many as 44 bromide and 15 ferrocenyl ω-substituents. Steric ω-substituent interactions appear to constrain the extent of place exchange. Ferrocenyl-substituted clusters are electroactive in CH2Cl2 solns. as adsorbed monolayers and as diffusing solutes. The mass transport behavior indicates that as many as 15 ferrocene units in a substituted cluster mol. can be oxidized at an electrode surface over a potential range as narrow as that required to oxidize a ferrocene monomer, i.e., the cluster has promise as a reagent that delivers multiple equiv. of redox activity at nearly identical formal potentials. The Au cores of the clusters also exhibit "double layer" charging behavior and are thus true mol. "nanoelectrodes".
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28Xit1amu7o%253D&md5=fba6de9071ffa8f720f2edf2f27f2b1e
    30. 30
      Luo, Z.; Hou, J.; Menin, L.; Ong, Q. K.; Stellacci, F. Evolution of the Ligand Shell Morphology during Ligand Exchange Reactions on Gold Nanoparticles. Angew. Chem., Int. Ed. 2017, 56, 13521– 13525,  DOI: 10.1002/anie.201708190
      30
      Evolution of the Ligand Shell Morphology during Ligand Exchange Reactions on Gold Nanoparticles
      Luo, Zhi; Hou, Jing; Menin, Laure; Ong, Quy Khac; Stellacci, Francesco
      Angewandte Chemie, International Edition (2017), 56 (43), 13521-13525CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH & Co. KGaA)
      Ligand exchange reactions are used to achieve nanoparticles coated with a mixt. of ligand mols. Currently, nothing is known on the evolution of the morphol. of the ligand shell during the reaction. The authors use a recently developed method (based on MALDI-TOF) to follow the evolution of the ligand shell compn. and morphol. during the reaction. The authors observe the expected evolution in compn. and we find that the ligand shell starts as a random mixt. and gradually evolves towards a patchy morphol. When the compn. has reached a plateau (i.e. when the reaction is generally assumed to be finished), the ligand shell morphol. keeps evolving for days, slowly approaching its equil. configuration.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXhsV2jtbbE&md5=3f7ec23e1c0ab344c278657b98f2d3b5
    31. 31
      Hurst, S. J.; Lytton-Jean, A. K.; Mirkin, C. A. Maximizing DNA Loading on a Range of Gold Nanoparticle Sizes. Anal. Chem. 2006, 78, 8313– 8318,  DOI: 10.1021/ac0613582
      31
      Maximizing DNA Loading on a Range of Gold Nanoparticle Sizes
      Hurst, Sarah J.; Lytton-Jean, Abigail K. R.; Mirkin, Chad A.
      Analytical Chemistry (2006), 78 (24), 8313-8318CODEN: ANCHAM; ISSN:0003-2700. (American Chemical Society)
      The authors have investigated the variables that influence DNA coverage on gold nanoparticles. The effects of salt concn., spacer compn., nanoparticle size, and degree of sonication have been evaluated. Maximum loading was obtained by salt aging the nanoparticles to ∼0.7 M NaCl in the presence of DNA contg. a poly(ethylene glycol) spacer. In addn., DNA loading was substantially increased by sonicating the nanoparticles during the surface loading process. Last, nanoparticles up to 250 nm in diam. were found have ∼2 orders of magnitude higher DNA loading than smaller (13-30 nm) nanoparticles, a consequence of their larger surface area. Stable large particles are attractive for a variety of biodiagnostic assays.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28XhtFyhtrfO&md5=1b1f5ac1386517068d1252b850112211
    32. 32
      Woehrle, G. H.; Brown, L. O.; Hutchison, J. E. Thiol-Functionalized, 1.5-nm Gold Nanoparticles through Ligand Exchange Reactions: Scope and Mechanism of Ligand Exchange. J. Am. Chem. Soc. 2005, 127, 2172– 2183,  DOI: 10.1021/ja0457718
      32
      Thiol-Functionalized, 1.5-nm Gold Nanoparticles through Ligand Exchange Reactions: Scope and Mechanism of Ligand Exchange
      Woehrle, Gerd H.; Brown, Leif O.; Hutchison, James E.
      Journal of the American Chemical Society (2005), 127 (7), 2172-2183CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      Ligand exchange reactions of 1.5-nm triphenylphosphine-stabilized nanoparticles with ω-functionalized thiols provides a versatile approach to functionalized, 1.5-nm gold nanoparticles from a single precursor. We describe the broad scope of this method and the first mechanistic investigation of thiol-for-phosphine ligand exchanges. The method is convenient and practical and tolerates a surprisingly wide variety of technol. important functional groups while producing very stable nanoparticles that essentially preserve the small core size and size dispersity of the precursor particle. The mechanistic studies reveal a novel three-stage mechanism that can be used to control the extent of ligand exchange. During the first stage of the exchange, AuCl(PPh3) is liberated, followed by replacement of the remaining phosphine ligands as PPh3 (assisted by gold complexes in soln.). The final stage involves completion and reorganization of the thiol-based ligand shell.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXmslWjsA%253D%253D&md5=22c2b3772b041df9a0e7b43ce580c9e5
    33. 33
      Shichibu, Y.; Negishi, Y.; Tsukuda, T.; Teranishi, T. Large-Scale Synthesis of Thiolated Au25 Clusters via Ligand Exchange Reactions of Phosphine-Stabilized Au11 Clusters. J. Am. Chem. Soc. 2005, 127, 13464– 13465,  DOI: 10.1021/ja053915s
      33
      Large-Scale Synthesis of Thiolated Au25 Clusters via Ligand Exchange Reactions of Phosphine-Stabilized Au11 Clusters
      Shichibu, Yukatsu; Negishi, Yuichi; Tsukuda, Tatsuya; Teranishi, Toshiharu
      Journal of the American Chemical Society (2005), 127 (39), 13464-13465CODEN: JACSAT; ISSN:0002-7863. (American Chemical Society)
      Phosphine-stabilized Au11 clusters in CHCl3 were reacted with glutathione (GSH) in H2O under a N2 atm. The resulting Au:SG clusters exhibit an optical absorption spectrum similar to that of Au25(SG)18, which was isolated as one of the major products from chem. prepd. Au:SG clusters (Negishi, Y. et al., 2005). Rigorous characterization by optical spectroscopy, electrospray ionization mass spectrometry, and polyacrylamide gel electrophoresis confirms that the Au25(SG)18 clusters were selectively obtained on the sub-100 mg scale by ligand exchange reaction under aerobic conditions. The ligand exchange strategy offers a practical and convenient method of synthesizing thiolated Au25 clusters on a large scale.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXpsleqtbc%253D&md5=e4409c1ceb3760ec45a4bb47ecb6c7d2
    34. 34
      Gittins, D.; Caruso, F. Spontaneous Phase Transfer of Nanoparticulate Metals from Organic to Aqueous Media. Angew. Chem., Int. Ed. 2001, 40, 3001– 3004,  DOI: 10.1002/1521-3773(20010817)40:16<3001::AID-ANIE3001>3.0.CO;2-5
      34
      Spontaneous phase transfer of nanoparticulate metals from organic to aqueous media
      Gittins, David I.; Caruso, Frank
      Angewandte Chemie, International Edition (2001), 40 (16), 3001-3004CODEN: ACIEF5; ISSN:1433-7851. (Wiley-VCH Verlag GmbH)
      A general method to efficiently transfer gold or palladium nanoparticles was developed. The method concerns the transfer from an org. solvent (in this case, toluene) to water. The method includes the following steps: prepn. of the metal nanoparticles in toluene by NaBH4 redn. of HAuCl4 or Na2PdCl4; phase transfer to water after addn. of 4-dimethylaminopyridine or an tetraalkyl ammonium salt.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3MXms1GrtLc%253D&md5=89f8237322967059b1bafa344632c4c9
    35. 35
      Rucareanu, S.; Gandubert, V. J.; Lennox, R. B. 4-(N,N-Dimethylamino)pyridine-Protected Au Nanoparticles: Versatile Precursors for Water- and Organic-Soluble Gold Nanoparticles. Chem. Mater. 2006, 18, 4674– 4680,  DOI: 10.1021/cm060793+
      35
      4-(N,N-Dimethylamino)pyridine-Protected Au Nanoparticles: Versatile Precursors for Water- and Organic-Soluble Gold Nanoparticles
      Rucareanu, Simona; Gandubert, Valerie J.; Lennox, R. Bruce
      Chemistry of Materials (2006), 18 (19), 4674-4680CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)
      Ligand-exchange reactions of 4-(N,N-dimethylamino)pyridine-capped gold nanoparticles (DMAP-Au NP) with functionalized thiols (RSH) were investigated. A simple, convenient, and facile synthesis method was developed. An important feature of this method is its requirement of only very modest quantities of excess thiol ligand. DMAP-Au NP prove to be versatile precursors for both water- and org.-sol. gold NP. DMAP is readily displaced by various functionalized thiols ranging from mercaptocarboxylic acids to ferrocene-terminated thiols. UV-vis spectroscopy and transmission electron microscopy (TEM) confirm that the mean diam. and the size dispersity of the initial DMAP-Au NP were retained upon ligand exchange. The RS-Au NP thus prepd. were efficiently purified by gel permeation chromatog. (GPC) with neither residual DMAP nor RSH detected in the final product.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD28Xoslalurs%253D&md5=c94989a5375149b7344a5c79ee5f90ba
    36. 36
      Manea, F.; Bindoli, C.; Polizzi, S.; Lay, L.; Scrimin, P. Expeditious Synthesis of Water-Soluble, Monolayer-Protected Gold Nanoparticles of Controlled Size and Monolayer Composition. Langmuir 2008, 24, 4120– 4124,  DOI: 10.1021/la703558y
      36
      Expeditious synthesis of water-soluble, monolayer-protected gold nanoparticles of controlled size and monolayer composition
      Manea, Flavio; Bindoli, Cristiano; Polizzi, Stefano; Lay, Luigi; Scrimin, Paolo
      Langmuir (2008), 24 (8), 4120-4124CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
      A protocol is reported for the prepn. of water-sol., thiol-monolayer-protected Au nanoparticles where dioctylamine was used as a stabilizing agent when the Au cluster is formed by using the two-phase Brust and Schiffrin procedure (1994). The amt. of amine controls the size of the nanoparticles in the 1.9-8.9 nm diam. range. The final stabilization of the Au clusters by addn. of functionalized thiols was performed under mild conditions compatible with most biomols. The procedure is suitable for a wide variety of functional groups present in the thiol and allows use of thiol mixts. with a precise control of their compn. in the monolayer. As a proof of the principle, examples of nanoparticles protected with thiols comprising functional groups ranging from polyethers, saccharides, polyamines and ammonium ions are reported.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXjtlOjsb4%253D&md5=54fb5aefa8364db309453d5dd1d951ac
    37. 37
      Brinas, R. P.; Maetani, M.; Barchi, J. J., Jr. A Survey of Place-Exchange Reaction for the Preparation of Water-Soluble Gold Nanoparticles. J. Colloid Interface Sci. 2013, 392, 415– 421,  DOI: 10.1016/j.jcis.2012.06.042
      There is no corresponding record for this reference.
    38. 38
      Wilcoxon, J. P.; Provencio, P. Etching and Aging Effects in Nanosize Au Clusters Investigated Using High-Resolution Size-Exclusion Chromatography. J. Phys. Chem. B 2003, 107, 12949– 12957,  DOI: 10.1021/jp027575y
      38
      Etching and Aging Effects in Nanosize Au Clusters Investigated Using High-Resolution Size-Exclusion Chromatography
      Wilcoxon, Jess P.; Provencio, Paula
      Journal of Physical Chemistry B (2003), 107 (47), 12949-12957CODEN: JPCBFK; ISSN:1520-6106. (American Chemical Society)
      The authors report expts. using high-resoln. size exclusion chromatog. (HRSEC), dynamic light scattering, and TEM to study the effects of aging of Au nanoclusters in the presence of surfactant ligands. The authors 1st describe observations of the role of thiols as etchants to produce clusters in a micelle-free synthesis by redn. of a metal-org. precursor. Clusters with large abundances are identified using HRSEC, and their sizes and optical properties are reported. The smallest, Dc ∼ 1 nm mol. sized Au clusters, with ∼1 closed at. shell, N ∼ 13 atoms, have nonclassical features in their room temp. absorbance spectra. The other dominant sub-populations also correspond closely to closed-shell structural stabilities. Contrary to the expectation that aging in soln. will always broaden the size dispersion and increase the av. size (Ostwald ripening), a narrowing of the size dispersion and change in av. size can occur with time under ambient conditions. In the presence of various chain length alkanethiols, an etching and size decrease usually occurs; in the case of weakly bound alkylated poly(ethylene oxide) surfactants, an increase in size with time is obsd.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD3sXosFWls7o%253D&md5=95c43cb21cc53357b2ac737efe2f8b80
    39. 39
      Shichibu, Y.; Negishi, Y.; Tsunoyama, H.; Kanehara, M.; Teranishi, T.; Tsukuda, T. Extremely High Stability of Glutathionate-Protected Au25 Clusters Against Core Etching. Small 2007, 3, 835– 839,  DOI: 10.1002/smll.200600611
      39
      Extremely high stability of glutathionate-protected Au25 clusters against core etching
      Shichibu, Yukatsu; Negishi, Yuichi; Tsunoyama, Hironori; Kanehara, Masayuki; Teranishi, Toshiharu; Tsukuda, Tatsuya
      Small (2007), 3 (5), 835-839CODEN: SMALBC; ISSN:1613-6810. (Wiley-VCH Verlag GmbH & Co. KGaA)
      The core-etching reaction by free glutathione is studied for glutathionate (SG)-protected Aun(SG)m clusters with n = 10-39 and m = 10-24. Only the Au25(SG)18 clusters remain unetched, whereas the Aun(SG)m clusters with n < 25 and n > 25 are transformed into a AuI:SG complex and stable Au25:SG, resp. The selective synthesis of thiolate (SR)-protected Au25:SR on a large scale may be possible.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2sXls1ajsr8%253D&md5=8137d9a5251b9c3093978cfb63bd0c7a
    40. 40
      Baranov, D.; Kadnikova, E. N. Synthesis and Characterization of Azidoalkyl-Functionalized Gold Nanoparticles as Scaffolds for “Click”-Chemistry Derivatization. J. Mater. Chem. 2011, 21, 6152– 6157,  DOI: 10.1039/c1jm10183h
      40
      Synthesis and characterization of azidoalkyl-functionalized gold nanoparticles as scaffolds for "click"-chemistry derivatization
      Baranov, Dmitry; Kadnikova, Ekaterina N.
      Journal of Materials Chemistry (2011), 21 (17), 6152-6157CODEN: JMACEP; ISSN:0959-9428. (Royal Society of Chemistry)
      Water-sol. Au nanoparticles prepd. by the citrate redn. method can be functionalized with 11-azidoundecane-1-thiol in a single-step procedure, which combines phase transfer and ligand exchange. The advantages of the authors' method include high reproducibility, low cost of Au nanoparticle prodn., and rapid and clean ligand exchange, with minimal intermediate steps and none of the laborious efforts. The resulting azido-functionalized nanoparticles were characterized by 1H NMR and UV-visible spectroscopy, and visualized by TEM. The Au nanocrystals preserve their shape and monodispersity after ligand exchange, so are promising scaffolds for further surface engineering via "click" chem. transformations.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXks12gsL0%253D&md5=e5a5e55eb0b66b0946a1c685c9c6b1e1
    41. 41
      Ojea-Jimenez, I.; Romero, F. M.; Bastus, N. G.; Puntes, V. Small Gold Nanoparticles Synthesized with Sodium Citrate and Heavy Water: Insights into the Reaction Mechanism. J. Phys. Chem. C 2010, 114, 1800– 1804,  DOI: 10.1021/jp9091305
      41
      Small Gold Nanoparticles Synthesized with Sodium Citrate and Heavy Water: Insights into the Reaction Mechanism
      Ojea-Jimenez, Isaac; Romero, Francisco M.; Bastus, Neus G.; Puntes, Victor
      Journal of Physical Chemistry C (2010), 114 (4), 1800-1804CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)
      The effect of solvent isotopic replacement (H for D) on the size of gold nanoparticles (Au NPs) prepd. by sodium citrate redn. has been investigated. With increasing replacement of water by deuterium oxide, smaller sizes of Au NPs are obtained, which is interpreted as a consequence of a faster redn. A mechanism in which a substitution complex, [AuCl3OCOC(OH)(CH2CO2)2]3-, is formed from [AuCl4]- and citrate ion(3-) prior to its rate-limiting disproportionation into products is suggested. This novel procedure offers an attractive alternative to the existing ones and opens a full range of possibilities for biol. studies.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXjs1ygtQ%253D%253D&md5=ce5e8025b1c81d8178148b652480a9b8
    42. 42
      Milette, J.; Toader, V.; Reven, L.; Lennox, R. B. Tuning the Miscibility of Gold Nanoparticles Dispersed in Liquid Crystals via the Thiol-for-DMAP Reaction. J. Mater. Chem. 2011, 21, 9043– 9050,  DOI: 10.1039/c1jm10553a
      42
      Tuning the miscibility of gold nanoparticles dispersed in liquid crystals via the thiol-for-DMAP reaction
      Milette, Jonathan; Toader, Violeta; Reven, Linda; Lennox, R. Bruce
      Journal of Materials Chemistry (2011), 21 (25), 9043-9050CODEN: JMACEP; ISSN:0959-9428. (Royal Society of Chemistry)
      Ligand exchange reactions using 4-5 nm 4-(N,N-dimethylamino)pyridine (DxMAP)-capped Au nanoparticles (AuNPs) formed the basis for synthesizing a family of liq. crystal (LC)-capped NPs for a rationalized miscibility in liq. crystal matrixes. NPs with ligand capping layers composed of Me(CH2)mSH (m = 5, 11) or 4'-(n-mercaptoalkyloxy)biphenyl-4-carbonitriles (CBO(CH2)nSH, n = 8, 12, 16) and their binary mixts. were prepd. The miscibility of the NPs in liq. crystals is sensitive to the ligand chain length and the d. of the LC ligands within the capping layers. Polarized optical microscopy and UV-visible data show that the NPs with only Me(CH2)mSH ligands are either immiscible or only partially disperse in the isotropic phases of 4-n-pentyl-4'-cyanobiphenyl (5CB) and 4-n-octyl-4'-cyanobiphenyl (8CB). NPs with CBO(CH2)nSH (n = 8, 12, 16) ligands or mixed Me(CH2)5SH/CBO(CH2)12SH ligand shells contg. 28% or 70% CBO(CH2)12SH ligand content partly disperse. However, NPs with a 1 : 1 Me(CH2)5SH/CBO(CH2)12SH ratio are completely miscible in isotropic 5CB up to at least 25% Au. In general, the derivatization methodol. developed here for mesogenic ligands provides in a complementary approach to thiol-for-thiol exchange for designing bifunctional AuNPs, offering the advantages of high reproducibility, access to a wide compn. range and no need for large excesses of valuable functionalized ligand.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXnsVWhurg%253D&md5=80c2c57f60eea1d9af5065acbfa59fc0
    43. 43
      Isaacs, S.; Cutler, E.; Park, J.; Lee, T.; Shon, Y. Synthesis of Tetraoctylammonium-Protected Gold Nanoparticles with Improved Stability. Langmuir 2005, 21, 5689– 5692,  DOI: 10.1021/la050656b
      43
      Synthesis of Tetraoctylammonium-Protected Gold Nanoparticles with Improved Stability
      Isaacs, Steven R.; Cutler, Erin C.; Park, Joon-Seo; Lee, T. Randall; Shon, Young-Seok
      Langmuir (2005), 21 (13), 5689-5692CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
      This paper shows that an introduction of thiosulfate anions in place of bromide anions greatly improves both chem. and thermal stability of tetraoctylammonium-protected gold nanoparticles. Tetraoctylammonium thiosulfate [(Oct)4N+-O3SS]-protected gold nanoparticles are synthesized by the redn. of (Oct)4N+-AuCl4 to Au(I)-SSO3-, followed by the addn. of sodium borohydride. The presence of thiosulfate anions instead of bromide anions on the surface of gold nanoparticles results in a significant dampening of the surface plasmon band of gold at 526 nm due to the strong interaction between thiosulfate and the gold nanoparticle surface. Cyanide decompn. and heating treatment studies suggest that (Oct)4N+-O3SS-protected nanoparticles have much higher overall stability compared to (Oct)4N+-Br-protected gold nanoparticles.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2MXktF2rtL0%253D&md5=437a6261ce515058fd1cb1715507187c
    44. 44
      Zhao, P.; Li, N.; Astruc, D. State of the Art in Gold Nanoparticle Synthesis. Coord. Chem. Rev. 2013, 257, 638– 665,  DOI: 10.1016/j.ccr.2012.09.002
      44
      State of the art in gold nanoparticle synthesis
      Zhao, Pengxiang; Li, Na; Astruc, Didier
      Coordination Chemistry Reviews (2013), 257 (3-4), 638-665CODEN: CCHRAM; ISSN:0010-8545. (Elsevier B.V.)
      A review. General principles and recent developments in the synthesis of gold nanoparticles (AuNPs) are reviewed. The "in situ" Turkevich-Frens and Brust-Schiffrin methods are still major synthetic routes, with citrate and thiolate ligands, resp., that were improved and extended to macromols. including biomacromols. with a large biomedical potential of optical and theranostic applications. Along this line, however, recently developed seed-growth methods have allowed a precise control of AuNP sizes in a broad range and multiple shapes. AuNPs and core-shell bimetallic MAuNPs loosely stabilized by nitrogen and oxygen atoms of embedding polymers and dendrimers and composite solid-state materials contg. AuNPs with supports including oxides, carbons, mesoporous materials and mol. org. frameworks (MOFs) have attracted much interest because of their catalytic applications.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXntlCmtg%253D%253D&md5=b399d1f3cce2440cf125b0f9394c6e5c
    45. 45
      Mourdikoudis, S.; Liz-Marzán, L. M. Oleylamine in Nanoparticle Synthesis. Chem. Mater. 2013, 25, 1465– 1476,  DOI: 10.1021/cm4000476
      45
      Oleylamine in Nanoparticle Synthesis
      Mourdikoudis, Stefanos; Liz-Marzan, Luis M.
      Chemistry of Materials (2013), 25 (9), 1465-1476CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)
      A review. Wet chem. in org. solvents has proven highly efficient for the prepn. of several types of metallic, metal-oxide, and semiconductor nanostructures. This Short Review focuses on the use of oleylamine (OAm) as a versatile reagent for the synthesis of various nanoparticle systems. The ability of OAm to act as a surfactant, solvent, and reducing agent, as a function of other synthesis parameters is described. The specific role of OAm either alone or in combination with other reactants to form nanostructures using a variety of org. or inorg. compds. as precursors is discussed. In certain cases OAm can form complex compds. with the metal ions of the corresponding precursor, leading to metastable compds. that can act as secondary precursors and thus be decompd. in a controlled way to yield nanoparticles. The OAm-stabilized particles can often be dispersed in different org. solvents yielding solns. with enhanced colloidal stability over long times and the potential to find applications in a no. of different fields.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3sXitlChsb4%253D&md5=f5c775c4fae0ffc3877262337f6a6e91
    46. 46
      Hiramatsu, H.; Osterloh, F. E. A Simple Large-Scale Synthesis of Nearly Monodisperse Gold and Silver Nanoparticles with Adjustable Sizes and with Exchangeable Surfactants. Chem. Mater. 2004, 16, 2509– 2511,  DOI: 10.1021/cm049532v
      46
      A Simple Large-Scale Synthesis of Nearly Monodisperse Gold and Silver Nanoparticles with Adjustable Sizes and with Exchangeable Surfactants
      Hiramatsu, Hiroki; Osterloh, Frank E.
      Chemistry of Materials (2004), 16 (13), 2509-2511CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)
      We report an inexpensive, versatile, and very reproducible method for the large-scale synthesis of organoamine-protected gold and silver nanoparticles in the 6-21 nm (Au) and 8-32 nm (Ag) size ranges and with polydispersities as low as 6.9 %.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD2cXktlaitb4%253D&md5=187f478bb9f29c2961ae775bdf11f1b5
    47. 47
      Lau, C. Y.; Duan, H.; Wang, F.; He, C. B.; Low, H. Y.; Yang, J. K. Enhanced Ordering in Gold Nanoparticles Self-Assembly through Excess Free Ligands. Langmuir 2011, 27, 3355– 3360,  DOI: 10.1021/la104786z
      47
      Enhanced Ordering in Gold Nanoparticles Self-Assembly through Excess Free Ligands
      Lau, Cindy Y.; Duan, Huigao; Wang, Fuke; He, Chao Bin; Low, Hong Yee; Yang, Joel K. W.
      Langmuir (2011), 27 (7), 3355-3360CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
      Self-assembly of nanometer-sized particles is an elegant and economical approach to achieve dense patterns over large areas beyond the resoln. and throughput capabilities of electron-beam lithog. In this paper, we present results of self-assembly of oleylamine-capped gold nanoparticles with 8.0 ± 0.3 nm diam. into densely packed and well-ordered monolayers with center-to-center distance of ∼11 nm. Self-assembly was done in a Langmuir-Blodgett trough and picked up onto Si substrates. The nanoparticles undesirably assembled within micrometer-sized "droplets" that were org. in nature. However, within these droplets, we obsd. that the addn. of the excess ligand, oleylamine, drastically enhanced the self-assembly of the nanoparticles into monolayers with near-perfect ordering. This approach has the potential use in templated self-assembly of nanoparticles for rearranging poorly ordered assembly into a commensurate prepatterned substrate.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXisVWmtbc%253D&md5=a7a4d5c688d84cd29ae800cd178e4a9b
    48. 48
      Ojea-Jiménez, I.; García-Fernández, L.; Lorenzo, J.; Puntes, V. F. Facile Preparation of Cationic Gold Nanoparticle-Bioconjugates for Cell Penetration and Nuclear Targeting. ACS Nano 2012, 6, 7692– 7702,  DOI: 10.1021/nn3012042
      48
      Facile preparation of cationic gold nanoparticle-bioconjugates for cell penetration and nuclear targeting
      Ojea-Jimenez, Isaac; Garcia-Fernandez, Lorena; Lorenzo, Julia; Puntes, Victor F.
      ACS Nano (2012), 6 (9), 7692-7702CODEN: ANCAC3; ISSN:1936-0851. (American Chemical Society)
      The present work faces the rising demand of cationic particles of different sizes for biol. applications, esp. in gene therapies and nanotoxicol. studies. A simple phase-transfer methodol. has been developed for the functionalization of gold nanoparticles (Au NPs) with a variety of ligands, both cationic and anionic in aq. soln., employing different nanocrystal sizes with narrow size distributions. Successful functionalization has been demonstrated by UV-vis spectroscopy, DLS, ζ-potential, and FTIR spectroscopy characterization of the particles before and after the phase transfer. The intracellular uptake of the differently charged Au NPs functionalized with peptidic biomols. was investigated with human fibroblasts (1BR3G) by ICP-MS anal. of the digested cells and confocal fluorescence microscopy, which showed increased internalization of the cationic bioconjugates. Nuclear targeting could be obsd. by TEM, suggesting that the cationic peptidic biomol. is acting as a nuclear localization signal.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC38XhtFGhs73F&md5=08ceeed256ef25bad68de14f6d10c974
    49. 49
      Zhang, T.; Guerin, D.; Alibart, F.; Vuillaume, D.; Lmimouni, K.; Lenfant, S.; Yassin, A.; Oçafrain, M.; Blanchard, P.; Roncali, J. Negative Differential Resistance, Memory, and Reconfigurable Logic Functions Based on Monolayer Devices Derived from Gold Nanoparticles Functionalized with Electropolymerizable TEDOT Units. J. Phys. Chem. C 2017, 121, 10131– 10139,  DOI: 10.1021/acs.jpcc.7b00056
      49
      Negative Differential Resistance, Memory, and Reconfigurable Logic Functions Based on Monolayer Devices Derived from Gold Nanoparticles Functionalized with Electropolymerizable TEDOT Units
      Zhang, T.; Guerin, D.; Alibart, F.; Vuillaume, D.; Lmimouni, K.; Lenfant, S.; Yassin, A.; Ocafrain, M.; Blanchard, P.; Roncali, J.
      Journal of Physical Chemistry C (2017), 121 (18), 10131-10139CODEN: JPCCCK; ISSN:1932-7447. (American Chemical Society)
      The authors report on hybrid memristive devices made of a network of gold nanoparticles (10 nm diam.) functionalized by tailored 3,4-(ethylenedioxy)thiophene (TEDOT) mols., deposited between two planar electrodes with nanometer and micrometer gaps (100 nm to 10 μm apart), and electropolymd. in situ to form a monolayer film of conjugated polymer with embedded gold nanoparticles (AuNPs). Elec. properties of these films exhibit two interesting behaviors: (i) a NDR (neg. differential resistance) behavior with a peak/valley ratio up to 17 and (ii) a memory behavior with an ON/OFF current ratio of ∼103-104. A careful study of the switching dynamics and programming voltage window is conducted demonstrating a nonvolatile memory. The data retention of the ON and OFF states is stable (tested up to 24 h), well controlled by the voltage, and preserved when repeating the switching cycles (800 in this study). The authors demonstrate reconfigurable Boolean functions in multiterminal connected NP/mol. devices.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2sXlvVGqur8%253D&md5=9c0b9db36c46c78d997f19a45a989980
    50. 50
      Peng, S.; Lee, Y.; Wang, C.; Yin, H.; Dai, S.; Sun, S. A Facile Synthesis of Monodisperse Au Nanoparticles and Their Catalysis of CO Oxidation. Nano Res. 2008, 1, 229– 234,  DOI: 10.1007/s12274-008-8026-3
      50
      A facile synthesis of monodisperse Au nanoparticles and their catalysis of CO oxidation
      Peng, Sheng; Lee, Youngmin; Wang, Chao; Yin, Hongfeng; Dai, Sheng; Sun, Shouheng
      Nano Research (2008), 1 (3), 229-234CODEN: NRAEB5; ISSN:1998-0124. (Springer)
      Monodisperse Au nanoparticles (NPs) were prepd. at room temp. via a burst nucleation of Au upon injection of the reducing agent t-butylamine-borane complex into a 1, 2,3,4-tetrahydronaphthalene soln. of HAuCl4.3H2O in the presence of oleylamine. The as-prepd. Au NPs show size-dependent surface plasmonic properties between 520 and 530 nm. They adopt an icosahedral shape and are polycryst. with multiple-twinned structures. When deposited on a graphitized porous carbon support, the NPs are highly active for CO oxidn., showing 100% CO conversion at -45°.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1MXhtFSjtrvE&md5=947e041704eee598d98afa7be9b38fa3
    51. 51
      Shen, C.; Hui, C.; Yang, T.; Xiao, C.; Tian, J.; Bao, L.; Chen, S.; Ding, H.; Gao, H. Monodisperse Noble-Metal Nanoparticles and Their Surface Enhanced Raman Scattering Properties. Chem. Mater. 2008, 20, 6939– 6944,  DOI: 10.1021/cm800882n
      51
      Monodisperse Noble-Metal Nanoparticles and Their Surface Enhanced Raman Scattering Properties
      Shen, Chengmin; Hui, Chao; Yang, Tianzhong; Xiao, Congwen; Tian, Jifa; Bao, Lihong; Chen, Shutang; Ding, Hao; Gao, Hongjun
      Chemistry of Materials (2008), 20 (22), 6939-6944CODEN: CMATEX; ISSN:0897-4756. (American Chemical Society)
      Monodisperse Au, Ag, and Au3Pd nanoparticles (NPs) with narrow size distribution are prepd. by direct reaction of the related metal salt with oleylamine in toluene. Oleylamine serves as both a reducing agent and a surfactant in the synthesis. The sizes and shape of these NPs are tuned by reaction temps. The hydrophobic oleylamine-coated NPs can be made water sol. by replacing oleylamine with 3-mercaptopropionic acid. Both surface plasmonic resonance (SPR) and surface enhanced Raman scattering (SERS) obsd. from the Au and Ag NPs are NP size- and surface-dependent.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BD1cXhtlSntbjE&md5=fededcedfe8dec139110092263c74a58
    52. 52
      Kluenker, M.; Mondeshki, M.; Nawaz Tahir, M.; Tremel, W. Monitoring Thiol-Ligand Exchange on Au Nanoparticle Surfaces. Langmuir 2018, 34, 1700– 1710,  DOI: 10.1021/acs.langmuir.7b04015
      52
      Monitoring Thiol-Ligand Exchange on Au Nanoparticle Surfaces
      Kluenker, Martin; Mondeshki, Mihail; Nawaz Tahir, Muhammad; Tremel, Wolfgang
      Langmuir (2018), 34 (4), 1700-1710CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
      Surface functionalization of nanoparticles (NPs) plays a crucial role in particle soly. and reactivity. It is vital for particle nucleation and growth as well as for catalysis. This raises the quest for functionalization efficiency and new approaches to probe the degree of surface coverage. The authors present an (in situ) proton NMR (1H NMR) study on the ligand exchange of oleylamine by 1-octadecanethiol as a function of the particle size and repeated functionalization on Au NPs. Ligand exchange is an equil. reaction assocd. with Nernst distribution, which often leads to incomplete surface functionalization following "std." literature protocols. The surface coverage with the ligand depends on the (i) repeated exchange reactions with large ligand excess, (ii) size of NPs, i.e., the surface curvature and reactivity, and (iii) mol. size of the ligand. As resonance shifts and extensive line broadening during and after the ligand exchange impede the evaluation of 1H NMR spectra, one- and two-dimensional 19F NMR techniques (correlation spectroscopy and diffusion ordered spectroscopy) with 1H,1H,2H,2H-perfluorodecanthiol as the fluorinated thiol ligand were employed to study the reactions. The enhanced resoln. assocd. with the spectral range of the 19F nucleus allowed carrying out a site-specific study of thiol chemisorption. The widths and shifts of the resonance signals of the different fluorinated carbon moieties were correlated with the distance to the thiol anchor group. In addn., the diffusion anal. revealed that moieties closer to the NP surface are characterized by a broader diffusion coeff. distribution as well as slower diffusion.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC1cXksVKlug%253D%253D&md5=704f5450a3f59b0ebca3ada2b0716683
    53. 53
      Malicki, M.; Hales, J. M.; Rumi, M.; Barlow, S.; McClary, L.; Marder, S. R.; Perry, J. W. Excited-State Dynamics and Dye-Dye Interactions in Dye-Coated Gold Nanoparticles with Varying Alkyl Spacer Lengths. Phys. Chem. Chem. Phys. 2010, 12, 6267– 6277,  DOI: 10.1039/b926938j
      There is no corresponding record for this reference.
    54. 54
      Köhntopp, A.; Dabrowski, A.; Malicki, M.; Temps, F. Photoisomerisation and Ligand-Controlled Reversible Aggregation of Azobenzene-Functionalised Gold Nanoparticles. Chem. Commun. 2014, 50, 10105– 10107,  DOI: 10.1039/C4CC02250E
      54
      Photoisomerisation and ligand-controlled reversible aggregation of azobenzene-functionalised gold nanoparticles
      Kohntopp Anja; Dabrowski Alexandra; Malicki Michal; Temps Friedrich
      Chemical communications (Cambridge, England) (2014), 50 (70), 10105-7 ISSN:.
      The photochemical behaviour of functionalised gold nanoparticles (AuNPs) carrying azobenzenethiolate-alkylthiolate monolayers was investigated. Repeated trans-cis and cis-trans isomerisation cycles could be performed in all cases with high efficiency. Reversible photoinduced aggregation was observed when azothiolates with long alkyl spacers (≥C7) were combined with short (C5) alkylthiolate coligands. The choice of a coligand thus offers control over the aggregation properties of the nanoparticles.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC2cbksl2mtw%253D%253D&md5=f39babf7b73acb89fac5db54f88be944
    55. 55
      Chu, Z.; Han, Y.; Kral, P.; Klajn, R. ”Precipitation on Nanoparticles”: Attractive Intermolecular Interactions Stabilize Specific Ligand Ratios on the Surfaces of Nanoparticles. Angew. Chem., Int. Ed. 2018, 57, 1– 6,  DOI: 10.1002/anie.201800673
      There is no corresponding record for this reference.
    56. 56
      Liu, X.; Hu, Y.; Stellacci, F. Mixed-Ligand Nanoparticles as Supramolecular Receptors. Small 2011, 7, 1961– 1966,  DOI: 10.1002/smll.201100386
      56
      Mixed-Ligand Nanoparticles as Supramolecular Receptors
      Liu, Xiang; Hu, Ying; Stellacci, Francesco
      Small (2011), 7 (14), 1961-1966CODEN: SMALBC; ISSN:1613-6810. (Wiley-VCH Verlag GmbH & Co. KGaA)
      Mixed-ligand-coated Au nanoparticles were synthesized using a naphthalene-terminated thiol (MNT) ligand and hexanethiol (HT). The mixed ligands self-assemble at the surface of nanoparticles forming a structure that interacts with PAHs through π-π interactions. Whereas the corresponding homoligand particles do not interact with PAHs in any detectable way, the mixed-ligand particles all have good binding ability to PAHs; specifically Au-MNT0.50HT0.50 binds to pyrene with a binding const. of 6.49 ± 5.71 × 104 M-1. Overall, mixed ligand-coated Au nanoparticles are versatile receptors for various PAHs. These easy-to-synthesize and easy-to-tailor particles can be used potentially for the detection and clean-up of PAH pollutants.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3MXovVert78%253D&md5=381714a92fef76835a56b251a0b6ee70
    57. 57
      van Lehn, R. C.; Ricci, M.; Silva, P. H.; Andreozzi, P.; Reguera, J.; Voïtchovsky, K.; Stellacci, F.; Alexander-Katz, A. Lipid Tail Protrusions Mediate the Insertion of Nanoparticles into Model Cell Membranes. Nat. Commun. 2014, 5, 4482,  DOI: 10.1038/ncomms5482
      57
      Lipid tail protrusions mediate the insertion of nanoparticles into model cell membranes
      Van Lehn, Reid C.; Ricci, Maria; Silva, Paulo H. J.; Andreozzi, Patrizia; Reguera, Javier; Voitchovsky, Kislon; Stellacci, Francesco; Alexander-Katz, Alfredo
      Nature Communications (2014), 5 (), 4482CODEN: NCAOBW; ISSN:2041-1723. (Nature Publishing Group)
      Recent work has demonstrated that charged gold nanoparticles (AuNPs) protected by an amphiphilic org. monolayer can spontaneously insert into the core of lipid bilayers to minimize the exposure of hydrophobic surface area to water. However, the kinetic pathway to reach the thermodynamically stable transmembrane configuration is unknown. Here, we use unbiased atomistic simulations to show the pathway by which AuNPs spontaneously insert into bilayers and confirm the results exptl. on supported lipid bilayers. The crit. step during this process is hydrophobic-hydrophobic contact between the core of the bilayer and the monolayer of the AuNP that requires the stochastic protrusion of an aliph. lipid tail into soln. This last phenomenon is enhanced in the presence of high bilayer curvature and closely resembles the putative pre-stalk transition state for vesicle fusion. To the best of our knowledge, this work provides the first demonstration of vesicle fusion-like behavior in an amphiphilic nanoparticle system.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXksVemu74%253D&md5=57dea1fc7554e69fae0dd6881d417867
    58. 58
      Harkness, K. M.; Hixson, B. C.; Fenn, L. S.; Turner, B. N.; Rape, A. C.; Simpson, C. A.; Huffman, B. J.; Okoli, T. C.; McLean, J. A.; Cliffel, D. E. A Structural Mass Spectrometry Strategy for the Relative Quantitation of Ligands on Mixed Monolayer-Protected Gold Nanoparticles. Anal. Chem. 2010, 82, 9268– 9274,  DOI: 10.1021/ac102175z
      58
      A Structural Mass Spectrometry Strategy for the Relative Quantitation of Ligands on Mixed Monolayer-Protected Gold Nanoparticles
      Harkness, Kellen M.; Hixson, Brian C.; Fenn, Larissa S.; Turner, Brian N.; Rape, Amanda C.; Simpson, Carrie A.; Huffman, Brian J.; Okoli, Tracy C.; McLean, John A.; Cliffel, David E.
      Analytical Chemistry (Washington, DC, United States) (2010), 82 (22), 9268-9274CODEN: ANCHAM; ISSN:0003-2700. (American Chemical Society)
      It is becoming increasingly common to use Au nanoparticles (AuNPs) protected by a heterogeneous mixt. of thiolate ligands, but many ligand mixts. on AuNPs cannot be properly characterized due to the inherent limitations of commonly used spectroscopic techniques. Using ion mobility-mass spectrometry (IM-MS), the authors have developed a strategy that allows measurement of the relative quantity of ligands on AuNP surfaces. This strategy is used for the characterization of 3 samples of mixed-ligand AuNPs: tiopronin:glutathione (av. diam. 2.5 nm), octanethiol:decanethiol (av. diam. 3.6 nm), and tiopronin:11-mercaptoundecyl(poly ethylene glycol) (av. diam. 2.5 nm). For validation purposes, the results obtained for tiopronin:glutathione AuNPs were compared to parallel measurements using NMR spectroscopy and mass spectrometry (MS) without ion mobility sepn. Relative quantitation measurements for NMR and IM-MS were in excellent agreement, with an av. difference of <1% relative abundance. IM-MS and MS without ion mobility sepn. were not comparable, due to a lack of ion signals for MS. The other 2 mixed-ligand AuNPs provide examples of measurements that cannot be performed using NMR spectroscopy.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC3cXhtlait7rI&md5=2abf76886e4f556c306657bd84a73dc9
    59. 59
      Badia, A.; Gao, W.; Singh, S.; Demers, L.; Cuccia, L.; Reven, L. Structure and chain dynamics of alkanethiol-capped gold colloids. Langmuir 1996, 12, 1262– 1269,  DOI: 10.1021/la9510487
      59
      Structure and Chain Dynamics of Alkanethiol-Capped Gold Colloids
      Badia, A.; Gao, W.; Singh, S.; Demers, L.; Cuccia, L.; Reven, L.
      Langmuir (1996), 12 (5), 1262-9CODEN: LANGD5; ISSN:0743-7463. (American Chemical Society)
      The structure and dynamical behavior of short and long chain alkanethiols, CH3(CH2)7SH and CH3(CH)17SH, and of a hydroxyalkanethiol, HO(CH2)16SH, adsorbed onto gold nanoparticles were studied by variable temp. solid-state 13C NMR spectroscopy. In both the soln. and solid state, the resonances of the first three carbons next to the sulfur headgroup disappear upon binding to the gold, indicating a strong interaction with the surface. A 13C-enriched sample, CH3(CH2)12*CH2SH/gold, displays a broad resonance centered at 42 ppm for the carbon next to the sulfur headgroup. Whereas the solid-state 13C shifts of CH3(CH2)7SH/gold are essentially the same as in soln., the methylene carbons of CH3(CH2)17SH and HO(CH2)16SH/gold shift downfield by 4.5 ppm in the solid state, indicating that the chains crystallize into an extended all-trans conformation. The high conformational order, along with reduced methylene proton line widths in the CH3(CH)17SH/gold sample, indicates that the chains are undergoing large-amplitude motions about their long axes. Mol. mobility increases toward the unbound ends which have a higher population of gauche conformers. Relaxation measurements show the coexistence of motionally restricted all-trans chains and a smaller population of liq.-like conformationally disordered chains in CH3(CH2)17SH/gold at room temp. The two types of chains are proposed to arise from close packing of the gold colloidal spheres, resulting in interstitial spaces and regions where chains of neighboring colloids can interdigitate to produce ordered domains. Phase transitions of the thiol-capped gold nanocrystals, which are detected by differential scanning calorimetry, are shown to involve a reversible disordering of the alkyl chains.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADyaK28XhtVCjt7o%253D&md5=3b6d40377060f5c2e5a8083c7a5dccb5
    60. 60
      Smith, A. M.; Marbella, L. E.; Johnston, K. A.; Hartmann, M. J.; Crawford, S. E.; Kozycz, L. M.; Seferos, D. S.; Millstone, J. E. Quantitative Analysis of Thiolated Ligand Exchange on Gold Nanoparticles Monitored by 1H NMR Spectroscopy. Anal. Chem. 2015, 87, 2771– 2778,  DOI: 10.1021/ac504081k
      60
      Quantitative Analysis of Thiolated Ligand Exchange on Gold Nanoparticles Monitored by 1H NMR Spectroscopy
      Smith, Ashley M.; Marbella, Lauren E.; Johnston, Kathryn A.; Hartmann, Michael J.; Crawford, Scott E.; Kozycz, Lisa M.; Seferos, Dwight S.; Millstone, Jill E.
      Analytical Chemistry (Washington, DC, United States) (2015), 87 (5), 2771-2778CODEN: ANCHAM; ISSN:0003-2700. (American Chemical Society)
      The authors use NMR spectroscopy methods to quantify the extent of ligand exchange between different types of thiolated mols. on the surface of gold nanoparticles. Specifically, the authors det. ligand d. values for single-moiety ligand shells and then use these data to describe ligand exchange behavior with a 2nd, thiolated mol. Using these techniques, the authors identify trends in gold nanoparticle functionalization efficiency with respect to ligand type, concn., and reaction time as well as distinguish between functionalization pathways where the new ligand may either replace the existing ligand shell (exchange) or add to it (backfilling). Specifically, gold nanoparticles functionalized with thiolated macromols., such as poly(ethylene glycol) (1 kDa), exhibit ligand exchange efficiencies ranging from 70% to 95% depending on the structure of the incoming ligand. Conversely, gold nanoparticles functionalized with small-mol. thiolated ligands exhibit exchange efficiencies ≥2% when exposed to thiolated mols. under identical exchange conditions. Taken together, the reported results provide advances in the fundamental understanding of mixed ligand shell formation and will be important for the prepn. of gold nanoparticles in a variety of biomedical, optoelectronic, and catalytic applications.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A528%3ADC%252BC2MXitlKku7Y%253D&md5=af058a3c89841630643b42c9bc642632
    61. 61
      Goldmann, C.; Ribot, F.; Peiretti, L. F.; Quaino, P.; Tielens, F.; Sanchez, C.; Chanéac, C.; Portehault, D. Quantified Binding Scale of Competing Ligands at the Surface of Gold Nanoparticles: The Role of Entropy and Intermolecular Forces. Small 2017, 13, 1604028,  DOI: 10.1002/smll.201604028
      There is no corresponding record for this reference.
    62. 62
      Luo, Z.; Marson, D.; Ong, Q. K.; Loiudice, A.; Kohlbrecher, J.; Radulescu, A.; Krause-Heuer, A.; Darwish, T.; Balog, S.; Buonsanti, R.; Svergun, D. I.; Posocco, P.; Stellacci, F. Quantitative 3D Determination of Self-Assembled Structures on Nanoparticles Using Small Angle Neutron Scattering. Nat. Commun. 2018, 9, 1343,  DOI: 10.1038/s41467-018-03699-7
      62
      Quantitative 3D determination of self-assembled structures on nanoparticles using small angle neutron scattering
      Luo Zhi; Ong Quy K; Stellacci Francesco; Marson Domenico; Posocco Paola; Loiudice Anna; Buonsanti Raffaella; Kohlbrecher Joachim; Radulescu Aurel; Krause-Heuer Anwen; Darwish Tamim; Balog Sandor; Svergun Dmitri I
      Nature communications (2018), 9 (1), 1343 ISSN:.
      The ligand shell (LS) determines a number of nanoparticles' properties. Nanoparticles' cores can be accurately characterized; yet the structure of the LS, when composed of mixture of molecules, can be described only qualitatively (e.g., patchy, Janus, and random). Here we show that quantitative description of the LS' morphology of monodisperse nanoparticles can be obtained using small-angle neutron scattering (SANS), measured at multiple contrasts, achieved by either ligand or solvent deuteration. Three-dimensional models of the nanoparticles' core and LS are generated using an ab initio reconstruction method. Characteristic length scales extracted from the models are compared with simulations. We also characterize the evolution of the LS upon thermal annealing, and investigate the LS morphology of mixed-ligand copper and silver nanoparticles as well as gold nanoparticles coated with ternary mixtures. Our results suggest that SANS combined with multiphase modeling is a versatile approach for the characterization of nanoparticles' LS.
      >> More from SciFinder ®
      https://chemport.cas.org/services/resolver?origin=ACS&resolution=options&coi=1%3ACAS%3A280%3ADC%252BC1MjgsVSltQ%253D%253D&md5=ee2b08eec010532488199ea0ed6369a7

  • Supporting Information

    Supporting Information

    ARTICLE SECTIONS
    Jump To

    The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.langmuir.8b00353.

    • TEM histograms of synthesized NPs; further experimental details; and NMR, TGA, MS, and UV–vis data (PDF)


    Terms & Conditions

    Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.

PDF [ 4MB]

Pair your accounts.

Export articles to Mendeley

Get article recommendations from ACS based on references in your Mendeley library.

Pair your accounts.

Export articles to Mendeley

Get article recommendations from ACS based on references in your Mendeley library.

You’ve supercharged your research process with ACS and Mendeley!

STEP 1:
Click to create an ACS ID

Please note: If you switch to a different device, you may be asked to login again with only your ACS ID.

Please note: If you switch to a different device, you may be asked to login again with only your ACS ID.

Please note: If you switch to a different device, you may be asked to login again with only your ACS ID.

MENDELEY PAIRING EXPIRED
Your Mendeley pairing has expired. Please reconnect