Neurotrophins (NTs), which are crucial for the functioning of the nervous system, are also known to regulate vascularization. Graphene-based materials may drive neural growth and differentiation, and, thus, have great potential in... more
Neurotrophins (NTs), which are crucial for the functioning of the nervous system, are also known to regulate vascularization. Graphene-based materials may drive neural growth and differentiation, and, thus, have great potential in regenerative medicine. In this work, we scrutinized the nano–biointerface between the cell membrane and hybrids made of neurotrophin-mimicking peptides and graphene oxide (GO) assemblies (pep−GO), to exploit their potential in theranostics (i.e., therapy and imaging/diagnostics) for targeting neurodegenerative diseases (ND) as well as angiogenesis. The pep−GO systems were assembled via spontaneous physisorption onto GO nanosheets of the peptide sequences BDNF(1-12), NT3(1-13), and NGF(1-14), mimicking the brain-derived neurotrophic factor (BDNF), the neurotrophin 3 (NT3), and the nerve growth factor (NGF), respectively. The interaction of pep−GO nanoplatforms at the biointerface with artificial cell membranes was scrutinized both in 3D and 2D by utilizing ...
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Aβ (1-40) can transfer from the aqueous phase to the bilayer and thus form stable ion-channel-like pores where the protein has alpha-helical conformation. The stability of the pores is due to the presence of the GXXXG motif. It has been... more
Aβ (1-40) can transfer from the aqueous phase to the bilayer and thus form stable ion-channel-like pores where the protein has alpha-helical conformation. The stability of the pores is due to the presence of the GXXXG motif. It has been reported that these ion-channel-like pores are stabilized by a Cα―H···O hydrogen bond that is established between a glycine of the GXXXG sequence of an alpha-helix and another amino acid of a vicinal alpha-helix. However, conflicting data are reported in the literature. Some authors have suggested that hydrogen bonding does not have a stabilizing function. Here we synthesized pentapeptides having a GXXXG motif to explore its role in pore stability. We used molecular dynamics simulations, quantum mechanics, and experimental biophysical techniques to determine whether hydrogen bonding was formed and had a stabilizing function in ion-channel-like structures. Starting from our previous molecular dynamics data, molecular quantum mechanics simulations, and...
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Graphene oxide (GO) nanosheets with different content in the defective carbon species bound to oxygen sp3 were functionalized with the angiogenin (ANG) protein, to create a novel nanomedicine for modulating angiogenic processes in cancer... more
Graphene oxide (GO) nanosheets with different content in the defective carbon species bound to oxygen sp3 were functionalized with the angiogenin (ANG) protein, to create a novel nanomedicine for modulating angiogenic processes in cancer therapies. The GO@ANG nanocomposite was scrutinized utilizing UV-visible and fluorescence spectroscopies. GO exhibits pro- or antiangiogenic effects, mostly attributed to the disturbance of ROS concentration, depending both on the total concentration (i.e., >100 ng/mL) as well as on the number of carbon species oxidized, that is, the C/O ratio. ANG is considered one of the most effective angiogenic factors that plays a vital role in the angiogenic process, often in a synergic role with copper ions. Based on these starting hypotheses, the GO@ANG nanotoxicity was assessed with the MTT colorimetric assay, both in the absence and in the presence of copper ions, by in vitro cellular experiments on human prostatic cancer cells (PC-3 line). Laser confoc...
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Materials Science, Wettability, Textile, Plasma, Atmospheric Pressure, and 12 moreContact angle, Atmospheric Pressure Plasma, Wetting, Métallurgie, Dielectric Barrier Discharge, Polyethylene terephthalate, X Ray Photoelectron Spectroscopy, Atmospheric Plasma, Plasma torch, plasma cleaning, Wicking, and Torch
Graphene oxide (GO), with its 2D nanocarbon structure but also many oxygenated defects, offers a convenient platform for surface tailoring, either covalent or non-covalent, owing to the great surface activity and good solution... more
Graphene oxide (GO), with its 2D nanocarbon structure but also many oxygenated defects, offers a convenient platform for surface tailoring, either covalent or non-covalent, owing to the great surface activity and good solution processability (1). The peculiar electronic, thermal and mechanical properties of graphene-based materials allow intensive promising applications in nanoelectronic devices, sensors, and nanocomposites. The present work tackles the functionalization of GO sheets to fabricate multifunctional nanoplatforms whose assembly states can be controlled in response to chemical stimuli for imaging and drug delivery applications (2). Specifically, the grafting onto the surface of GO nanosheets of pH-responsive acrylate (PAA) oligomers was optimized as function of the surface charge and scrutinized by a multitechnique approach of spectroscopic (Raman, X-ray photoelectron spectroscopy, UV-visible, fluorescence) and microscopic (confocal and atomic force microscopy, scanning ...
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Angiogenin (ANG), an endogenous protein that plays a key role in cell growth and survival, has been scrutinised here as promising nanomedicine tool for the modulation of pro-/ anti-angiogenic processes in brain cancer therapy.... more
Angiogenin (ANG), an endogenous protein that plays a key role in cell growth and survival, has been scrutinised here as promising nanomedicine tool for the modulation of pro-/ anti-angiogenic processes in brain cancer therapy. Specifically, peptide fragments from the putative cell membrane binding domain (residues 60-68) of the protein were used in this study to obtain peptide-functionalised spherical gold nanoparticles (AuNPs) of about 10 nm and 30 nm in optical and hydrodynamic size, respectively. Different hybrid biointerfaces were fabricated by peptide physical adsorption (Ang60-68) or chemisorption (the cysteine analogous Ang60-68Cys) at the metal nanoparticle surface, and the cellular assays were performed in the comparison with ANG-functionalised AuNPs. Cellular treatments were performed both in basal and in copper-supplemented cell culture medium, to scrutinise the synergic effect of the metal, which is another known angiogenic factor. Two brain cell lines were investigated ...
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Abstract Atomistic Molecular Dynamics (MD) simulations of both the physisorption process and the hydration behavior of the aggregate consisting of gemcitabine (GEM) - poly(acrylic acid) (PAA) - graphene oxide (GO) are performed in... more
Abstract Atomistic Molecular Dynamics (MD) simulations of both the physisorption process and the hydration behavior of the aggregate consisting of gemcitabine (GEM) - poly(acrylic acid) (PAA) - graphene oxide (GO) are performed in explicit solvent medium at two different pH values. The different ionization of pH sensitive groups characterizing the aggregate influences the energy of physisorption and the hydration shell around the complex. The decrease of negative charge density, occurring at acid pH, facilitates the physisorption process between PAA and GO. On the other hand, at the same pH value, a weaker interaction between GEM and PAA is observed. MD simulations show a partial physisorption of the drug from the polymer at pH = 4.0. pH change affects also morphology of GO sheet which is more extended at basic pH value due to intrasheet electrostatic interactions. Radial distribution function (RDF) indicates that carboxylate oxygens of PAA and alkoxide oxygens of GO strongly attract dipolar water molecules, thus affecting the hydration shell around the complex in comparison with unionized GO and bulk water. Finally, an analysis based on H-bond correlation function clearly shows that: (a) hydrogen bond between both carboxylate and alkoxide oxygen atoms are longer lived than those observed in unionized GO and bulk water; (b) RDF decays slower for PAA ( f = 0.8) with respect to ionized GO, hence indicating that COO − groups bind water molecules stronger than R-O − .
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A green fluorescent RGD peptide–silver nanoparticle platform to target integrin receptors in cells and bacterial studies.
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Geochemistry, Chemistry, Fluorescence Spectroscopy, Protein adsorption, Kinetics, and 12 morePHOTOELECTRON SPECTROSCOPY, Adsorption, Contact angle, Interdisciplinary Engineering, Ion Beam, Chemical Composition, Surface free energy, X Ray Photoelectron Spectroscopy, Human Serum Albumin (HSA), Ion Irradiation, Adsorption kinetic, and Human serum albumin
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Genetics, Chemistry, Coordination Chemistry, NMR Spectroscopy, Medicine, and 14 moreAngiogenesis, Humans, Circular Dichroism, Copper, Peptide, Neuroblastoma, Molecular sciences, Amino Acid Profile, Peptide and Peptidomimetic Chemistry, Protein Binding, Hydrogen-Ion Concentration, Cell Survival, Angiogenin, and binding sites
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Angiogenin (Ang) is a potent angiogenic protein that is overexpressed in many types of cancer at concentration values correlated to the tumor aggressiveness. Here, by means of an integrated multi-technique approach based on... more
Angiogenin (Ang) is a potent angiogenic protein that is overexpressed in many types of cancer at concentration values correlated to the tumor aggressiveness. Here, by means of an integrated multi-technique approach based on crystallographic, spectrometric and spectroscopic analyses, we demonstrate that the anti-cancer drug oxaliplatin efficiently binds angiogenin. Microscopy cellular studies, carried out on the prostate cancer cell (PC-3) line , show that oxaliplatin inhibits the angiogenin prompting effect on cell proliferation and migration, which are typical features of angiogenesis process. Overall, our findings point to angiogenin as a possible target of oxaliplatin, thus suggesting a potential novel mechanism for the antineoplastic activity of this platinum drug and opening the avenue to novel approaches in the combined anti-cancer anti-angiogenic therapy.
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Graphene oxide (GO) is a bidimensional novel material that exhibits high biocompatibility and angiogenic properties, mostly related to the intracellular formation of reactive oxygen species (ROS). In this work, we set up an experimental... more
Graphene oxide (GO) is a bidimensional novel material that exhibits high biocompatibility and angiogenic properties, mostly related to the intracellular formation of reactive oxygen species (ROS). In this work, we set up an experimental methodology for the fabrication of GO@peptide hybrids by the immobilization, via irreversible physical adsorption, of the Ac-(GHHPH)4-NH2 peptide sequence, known to mimic the anti-angiogenic domain of the histidine-proline-rich glycoprotein (HPRG). The anti-proliferative capability of the graphene-peptide hybrids were tested in vitro by viability assays on prostate cancer cells (PC-3 line), human neuroblastoma (SH-SY5Y), and human retinal endothelial cells (primary HREC). The anti-angiogenic response of the two cellular models of angiogenesis, namely endothelial and prostate cancer cells, was scrutinized by prostaglandin E2 (PGE2) release and wound scratch assays, to correlate the activation of inflammatory response upon the cell treatments with the ...
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In this work we report on the synthesis and physiochemical/biological characterization of a peptide encompassing the first thirteen residues of Neurotrophin-3 (NT-3). The protein capability to promote the neurite outgrowth...
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Noble metal nanomaterials, such as gold or silver nanoparticles, exhibit unique photonic, electronic, catalytic and therapeutic properties. The high versatility in their synthesis, especially size and shape features, as well as in the... more
Noble metal nanomaterials, such as gold or silver nanoparticles, exhibit unique photonic, electronic, catalytic and therapeutic properties. The high versatility in their synthesis, especially size and shape features, as well as in the surface functionalization by, e.g., physisorption, direct chemisorption of thiol derivatives and covalent binding through bifunctional linkers or specific affinity interactions, prompted their widespread and rising use as multifunctional platforms for theranostic purposes. In this paper, the recent developments of gold and silver nanoparticles for application in biosensing, medical imaging, diagnosis and therapy is reviewed from the following five aspects: (1) the gold and silver nanomaterials intrinsic properties of biomedical interest; (2) the synthesis of noble metal nanoparticle by chemical, physical and biological/green processes; (3) the applications of gold and silver nanoparticles in imaging, diagnostic and therapeutic mode; (4) the surface functionalization processes for targeting, controlled drug loading and release, triggered pathways of cellular uptake and tissue distribution; and (5) nanotoxicity. The historical developments and the most recent applications have been focused on, together with suggested strategies for future more efficacious, targeted delivery.
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Background In preparation for the 2021 revision of the European Union Tobacco Products Directive, the Scientific Committee on Health, Environmental and Emerging Risks (SCHEER) has posted its Preliminary Opinion on Electronic Cigarettes.... more
Background In preparation for the 2021 revision of the European Union Tobacco Products Directive, the Scientific Committee on Health, Environmental and Emerging Risks (SCHEER) has posted its Preliminary Opinion on Electronic Cigarettes. They concluded that e-cigarettes only achieve a sub-optimal level of protection of human health. In this paper, we provide evidence that the Opinion’s conclusions are not adequately backed up by scientific evidence and did not discuss the potential health benefits of using alternative combustion-free nicotine-containing products as substitute for tobacco cigarettes. Methods Searches for articles were conducted in PubMed and by citation chasing in Google Scholar. Articles were also retrieved with a review of references in major publications. Primary data from World Health Organization surveys, the conclusions of reviews, and peer-reviewed non-industry studies were cited to address errors and omissions identified in the Opinion. Results The Opinion omi...
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In this study, graphene oxide (GO) and reduced-thiolated GO (rGOSH) were used as 2D substrate to fabricate nanocomposites with nanoparticles of gold nanospheres (AuNS) or nanorods (AuNR), via in situ reduction of the metal salt precursor... more
In this study, graphene oxide (GO) and reduced-thiolated GO (rGOSH) were used as 2D substrate to fabricate nanocomposites with nanoparticles of gold nanospheres (AuNS) or nanorods (AuNR), via in situ reduction of the metal salt precursor and seed-mediated growth processes. The plasmonic sensing capability of the gold-decorated nanosheets were scrutinized by UV-visible (UV-VIS) spectroscopy. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetric analyses (TGA), and atomic force microscopy (AFM) were performed in order to prove the actual reduction that occurred concomitantly with the thiolation of GO, the increase in the hydrophobic character as well as the size, and preferential gathering of the gold nanoparticles onto the nanosheet substrates, respectively. Moreover, the theoretical electronic and infrared absorption (UV-VIS and IR) spectra were calculated within a time-dependent approach of density functional theory (DFT). Eventually, in...
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Nerve growth factor (NGF) is a protein necessary for development and maintenance of the sympathetic and sensory nervous systems. We have previously shown that the NGF N-terminus peptide NGF(1-14) is sufficient to activate TrkA signaling... more
Nerve growth factor (NGF) is a protein necessary for development and maintenance of the sympathetic and sensory nervous systems. We have previously shown that the NGF N-terminus peptide NGF(1-14) is sufficient to activate TrkA signaling pathways essential for neuronal survival and to induce an increase in brain-derived neurotrophic factor (BDNF) expression. Cu2+ ions played a critical role in the modulation of the biological activity of NGF(1-14). Using computational, spectroscopic, and biochemical techniques, here we report on the ability of a newly synthesized peptide named d-NGF(1-15), which is the dimeric form of NGF(1-14), to interact with TrkA. We found that d-NGF(1-15) interacts with the TrkA-D5 domain and induces the activation of its signaling pathways. Copper binding to d-NGF(1-15) stabilizes the secondary structure of the peptides, suggesting a strengthening of the noncovalent interactions that allow for the molecular recognition of D5 domain of TrkA and the activation of...
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In this work, nanobiohybrids of plasmonic gold nanoparticles (AuNP, anti-angiogenic) and a peptide mimicking the vascular endothelial growth factor (VEGF, pro-angiogenic) were assembled and scrutinized in terms of physicochemical... more
In this work, nanobiohybrids of plasmonic gold nanoparticles (AuNP, anti-angiogenic) and a peptide mimicking the vascular endothelial growth factor (VEGF, pro-angiogenic) were assembled and scrutinized in terms of physicochemical characterization, including optical properties, surface charge, surface chemical structure and morphology of the bioengineered metal nanoparticles, for their potential application as multifunctional theranostic (i.e., therapy + sensing) nanoplatform (AuNP/VEGF). Specifically, a peptide sequence encompassing the VEGF cellular receptor domain 73–101 (VEGF73–101) and its single point cysteine mutated were immobilized onto AuNP by physi- and chemi-sorption, respectively. The new hybrid systems were characterized by means of a multitechnique approach, including dynamic light scattering (DLS) analyses, zeta potential (ZP), spectroscopic (UV-Vis, FT-IR, XPS), spectrometric (TOF-SIMS) and microscopic (AFM, SEM) techniques. Proof-of-work cellular experiments in huma...
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Angiogenesis plays a key role in the wound healing process, involving the migration, growth, and differentiation of endothelial cells. Angiogenesis is controlled by a strict balance of different factors, and among these, the angiogenin... more
Angiogenesis plays a key role in the wound healing process, involving the migration, growth, and differentiation of endothelial cells. Angiogenesis is controlled by a strict balance of different factors, and among these, the angiogenin protein plays a relevant role. Angiogenin is a secreted protein member of the ribonuclease superfamily that is taken up by cells and translocated to the nucleus when the process of blood vessel formation has to be promoted. However, the chemical signaling that activates the protein, normally present in the plasma, and the transport pathways through which the protein enters the cell are still largely unclear. Copper is also an angiogenic factor that regulates angiogenin expression and participates in the activation of common signaling pathways. The interaction between angiogenin and copper could be a relevant mechanism in regulating the formation of new blood vessel pathways and paving the way to the development of new drugs for chronic non-healing wou...
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The Spontaneous Symmetry Breaking (SSB) phenomenon is a natural event in which a system changes its symmetric state, apparently reasonless, in an asymmetrical one. Nevertheless, this occurrence could be hiding unknown inductive forces. An... more
The Spontaneous Symmetry Breaking (SSB) phenomenon is a natural event in which a system changes its symmetric state, apparently reasonless, in an asymmetrical one. Nevertheless, this occurrence could be hiding unknown inductive forces. An intriguing investigation pathway uses supramolecular aggregates of suitable achiral porphyrins, useful to mimic the natural light-harvesting systems (as chlorophyll). Using as SSB probe supramolecular aggregates of 5,10,15,20-tetrakis[p(ω-methoxypolyethyleneoxy)phenyl]porphyrin (StarP), a non-ionic achiral PEGylated porphyrin, we explore here its interaction with weak asymmetric thermal gradients fields. The cross-correlation of the experimental data (circular dichroism, confocal microscopy, atomic force microscopy, and cryo-transmission electron microscopy) revealed that the used building blocks aggregate spontaneously, organizing in flag-like structures whose thermally-induced circular dichroism depends on their features. Finally, thermal gradien...
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Nowdays, neurodegenerative diseases represent a great challenge from both the therapeutic and diagnostic points of view. Indeed, several physiological barriers of the body, including the blood brain barrier (BBB), nasal, dermal, and... more
Nowdays, neurodegenerative diseases represent a great challenge from both the therapeutic and diagnostic points of view. Indeed, several physiological barriers of the body, including the blood brain barrier (BBB), nasal, dermal, and intestinal barriers, interpose between the development of new drugs and their effective administration to reach the target organ or target cells at therapeutic concentrations. Currently, the nose-to-brain delivery with nanoformulations specifically designed for intranasal administration is a strategy widely investigated with the goal to reach the brain while bypassing the BBB. To produce nanosystems suitable to study both in vitro and/or in vivo cells trafficking for potential nose-to-brain delivery route, we prepared and characterized two types of fluorescent poly(ethylene glycol)-methyl-ether-block-poly(lactide-co-glycolide) (PLGA–PEG) nanoparticles (PNPs), i.e., Rhodamine B (RhB) dye loaded- and grafted- PNPs, respectively. The latter were produced by...
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The angiogenin protein (ANG) is one of the most potent endogenous angiogenic factors. In this work we characterized by means of potentiometric, spectroscopic and voltammetric techniques, the copper complex species formed with peptide... more
The angiogenin protein (ANG) is one of the most potent endogenous angiogenic factors. In this work we characterized by means of potentiometric, spectroscopic and voltammetric techniques, the copper complex species formed with peptide fragments derived from the N-terminal domain of the protein, encompassing the sequence 1-17 and having free amino, Ang1-17, or acetylated N-terminus group, AcAng1-17, so to explore the role of amino group in metal binding and cellular copper uptake. The obtained data show that amino group is the main copper anchoring site for Ang1-17. The affinity constant values, metal coordination geometry and complexes redox-potentials strongly depend, for both peptides, on the number of copper equivalents added. Confocal laser scanning microscope analysis on neuroblastoma cells showed that in the presence of one equivalent of copper ion, the free amino Ang1-17 increases cellular copper uptake while the acetylated AcAng1-17 strongly decreases the intracellular metal ...
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In this work, we aimed to develop a hybrid theranostic nano-formulation based on gold nanoparticles (AuNP)—having a known anti-angiogenic character—and the angiogenin (ANG), in order to tune the angiogenesis-related phases involved in the... more
In this work, we aimed to develop a hybrid theranostic nano-formulation based on gold nanoparticles (AuNP)—having a known anti-angiogenic character—and the angiogenin (ANG), in order to tune the angiogenesis-related phases involved in the multifaceted process of the wound healing. To this purpose, spherical were surface “decorated” with three variants of the protein, namely, the recombinant (rANG), the wild-type, physiologically present in the human plasma (wtANG) and a new mutant with a cysteine substitution of the serine at the residue 28 (S28CANG). The hybrid biointerface between AuNP and ANG was scrutinized by a multi-technique approach based on dynamic light scattering, spectroscopic (UV-visible, circular dichroism) and microscopic (atomic force and laser scanning confocal) techniques. The analyses of optical features of plasmonic gold nanoparticles allowed for discrimination of different adsorption modes—i.e.; predominant physisorption and/or chemisorption—triggered by the ANG...
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In this study, a novel multifunctional nanoplatform based on core-shell nanoparticles of spherical gold nanoparticles (AuNPs) capped with low and high molecular weight (200 and 700 kDa) hyaluronic acid (HA), was assembled via a green,... more
In this study, a novel multifunctional nanoplatform based on core-shell nanoparticles of spherical gold nanoparticles (AuNPs) capped with low and high molecular weight (200 and 700 kDa) hyaluronic acid (HA), was assembled via a green, one-pot redox synthesis method at room temperature. A multitechnique characterization approach by UV-visible spectroscopy, dynamic light scattering and atomic force microscopy pointed to the effective ‘surface decoration’ of the gold nanoparticles by HA, resulting in different grafting densities of the biopolymer chains at the surface of the metal nanoparticle, which in turn affected the physicochemical properties of the nanoparticles. Specifically, the spectral features of the gold plasmonic peak (and the related calculated optical size), the hydrodynamic diameter and the nanoparticle stability were found to depend on the molecular weight of the HA. The CD44-targeting capability of HA-functionalized gold nanoparticles was tested in terms of antibacter...
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The opossum is a peculiar model of immunity to prion diseases. Here we scrutinised the bis-decarepeat peptide sequence of opossum prion (Op_bis-deca) protein by a multitechnique approach, with a combined...
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Point-of-care nanobiosensors have tremendous potential to revolutionize the future of personalized nanomedicine, especially for the simultaneous diagnosis and therapy, which takes the name of theranostics [...]
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Background: The metal ions dyshomeostasis is increasingly recognized to play a crucial role in the development of aging-related neurodegenerative diseases. Metal trafficking in the brain is related to proteins regulating both uptake and... more
Background: The metal ions dyshomeostasis is increasingly recognized to play a crucial role in the development of aging-related neurodegenerative diseases. Metal trafficking in the brain is related to proteins regulating both uptake and efflux of metals in neurons. Different pathways may occur, depending on specific binding features of metallo-protein complexes. In particular, copper, zinc and iron are recognized to influence the biochemistry of proteins involved in neurodegeneration (for instance Aβ and α-synuclein), as well as those playing a crucial role in neuronal development and efficiency (neurotrophins). Nowadays the application of peptide-based drugs is widespread for different pathologies, but the short lifetime in vivo due to proteolysis and other shortcomings still limit their use. Methods: A structured search was performed about the state of the art on: i) peptidomimetic approaches used to obtain peptides mimicking the metal binding activities of proteins involved in ne...
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The repeated use of conventional synthetic pesticides in crop protection leads to resistance development by pests along with a negative impact on the environment, particularly non-target arthropods. Plant-derived active compounds, such as... more
The repeated use of conventional synthetic pesticides in crop protection leads to resistance development by pests along with a negative impact on the environment, particularly non-target arthropods. Plant-derived active compounds, such as essential oils (EOs), play a key role in sustainably controlling pests. The lethal and sublethal activity of citrus peel EOs as emulsions and included in polyethylene glycol (PEG) nanoparticles (EO-NPs) was determined against the invasive tomato pest Tuta absoluta. Their effects on the plants were also assessed. The results showed an overall good insecticidal activity of the compounds tested, with a higher mortality through contact on eggs and larvae by EO emulsions and through ingestion on larvae by EO-NPs. The nanoformulation also significantly reduced the visible toxic effects on the plants. The data collected suggest that these natural compounds, especially when nanoformulated, could be successfully used in integrated pest management programs f...
Increasing evidence is accumulating, showing that neurodegenerative disorders are somehow associated with the toxicity of amyloid aggregates, metal ion dyshomeostasis as well as with products generated by oxidative stress. Within the... more
Increasing evidence is accumulating, showing that neurodegenerative disorders are somehow associated with the toxicity of amyloid aggregates, metal ion dyshomeostasis as well as with products generated by oxidative stress. Within the biological oxidation products, acrolein does have a prominent role. A promising strategy to deal with the above neurogenerative disorders is to use multi-functions bio-molecules. Herein, we show how a class of bio-conjugates takes advantage of the antiaggregating, antioxidant and antiglycating properties of trehalose and carnosine. Their ability to sequester acrolein and to inhibit both self- and metal-induced aggregation is here reported. The copper(II) coordination properties of a new trehalose-carnosine conjugate and the relative antioxidant effects have also been investigated.
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A variety of fluorescent probes are proposed to monitor the intracellular copper content. So far, none of the probes have been evaluated for their potential to inhibit copper-associated intracellular oxidative stress. Herein, we studied... more
A variety of fluorescent probes are proposed to monitor the intracellular copper content. So far, none of the probes have been evaluated for their potential to inhibit copper-associated intracellular oxidative stress. Herein, we studied the ability of a fluorescent copper probe, OBEP-CS1, to inhibit intracellular oxidative stress associated with an amyloid β (Aβ) peptide-copper complex. The data showed that OBEP-CS1 completely inhibits the copper-catalyzed oxidation as well as decarboxylation/deamination of Aβ1-16. Moreover, the cell imaging experiments confirmed that OBEP-CS1 can inhibit Aβ-Cu(II)-catalyzed reactive oxygen species production in SH-SY5Y cells. We also demonstrated that Aβ1-16 peptide can bind intracellular copper and thereby exert oxidative stress.
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The aggregation of amyloid-Aβ (Aβ) on lipid bilayers has been implicated as a mechanism by which Aβ exerts its toxicity in Alzheimer's disease (AD). Lipid bilayer thinning has been observed during both oxidative stress and protein... more
The aggregation of amyloid-Aβ (Aβ) on lipid bilayers has been implicated as a mechanism by which Aβ exerts its toxicity in Alzheimer's disease (AD). Lipid bilayer thinning has been observed during both oxidative stress and protein aggregation in AD, but whether these pathological modifications of the bilayer correlate with Aβ misfolding is unclear. Here, we studied peptide-lipid interactions in synthetic bilayers of the short-chain lipid dilauroyl phosphatidylcholine (DLPC) as a simplified model for diseased bilayers to determine their impact on Aβ aggregate, protofibril, and fibril formation. Aβ aggregation and fibril formation in membranes composed of dioleoyl phosphatidylcholine (DOPC) or 1- palmitoyl-2-oleoyl phosphatidylcholine (POPC) mimicking normal bilayers served as controls. Differences in aggregate formation and stability were monitored by a combination of thioflavin-T fluorescence, circular dichroism, AFM, TEM, and NMR. Despite the ability of all three lipid bilayers...
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Semax is a heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) that encompasses the sequence 4-7 of N-terminal domain of the adrenocorticotropic hormone and a C-terminal Pro-Gly-Pro tripeptide. N-terminal amino group acetylation (Ac-Semax)... more
Semax is a heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) that encompasses the sequence 4-7 of N-terminal domain of the adrenocorticotropic hormone and a C-terminal Pro-Gly-Pro tripeptide. N-terminal amino group acetylation (Ac-Semax) modulates the chemical and biological properties of parental peptide, modifying the ability of Semax to form complex species with Cu(II) ion. At physiological pH, the main complex species formed by Ac-Semax, [CuLH-2](2-), consists in a distorted CuN3O chromophore with a weak apical interaction of the methionine sulphur. Such a complex differs from the Cu(II)-Semax complex system, which exhibits a CuN4 chromophore. The reduced ligand field affects the [CuLH-2](2-) formal redox potential, which is more positive than that of Cu(II)-Semax corresponding species. In the amino-free form, the resulting complex species is redox-stable and unreactive against ascorbic acid, unlike the acetylated form. Semax acetylation did not protect from Cu(II) induced toxicity on a SH-SY5Y neuroblastoma cell line, thus demonstrating the crucial role played by the free NH2 terminus in the cell protection. Since several brain diseases are associated either to Cu(II) or Zn(II) dyshomeostasis, here we characterized also the complex species formed by Zn(II) with Semax and Ac-Semax. Both peptides were able to form Zn(II) complex species with comparable strength. Confocal microscopy imaging confirmed that peptide group acetylation does not affect the Zn(II) influx in neuroblastoma cells. Moreover, a punctuate distribution of Zn(II) within the cells suggests a preferred subcellular localization that might explain the zinc toxic effect. A future perspective can be the use of Ac-Semax as ionophore in antibody drug conjugates to produce a dysmetallostasis in tumor cells.
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A novel substrate for preparation of supported lipid bilayers (SLBs), smooth at the subnanometer scale and of variable thickness from ten to several hundred nanometers, was developed by surface oxidation of spin-coated... more
A novel substrate for preparation of supported lipid bilayers (SLBs), smooth at the subnanometer scale and of variable thickness from ten to several hundred nanometers, was developed by surface oxidation of spin-coated poly(hydroxymethylsiloxane) (PHMS) films. The deposited polymeric thin films were modified by a combination of oxygen plasma and thermal treatment (PHMS(ox)), in order to convert the outermost surface layer of the polymer film to a stable SiO(2) film, suitable for SLB formation. The hydrophilic, SiO(2)-like surfaces were characterized by XPS, wetting angle, ellipsometry, and AFM. Lipid bilayers were formed on this surface using the well-known vesicle adsorption-rupture-fusion process, usually performed on glass or vapor-deposited SiO(2). Reproducible formation of homogeneous SLBs of different compositions (POPC, DOEPC, and POPC/DOPS) was demonstrated on the new SiO(2) surface by quartz crystal microbalance with dissipation (QCM-D), surface plasmon resonance (SPR), and optical reflectometry measurements. The SLB formation kinetics on the PHMS(ox)-coated sensors showed very similar characteristics, for all investigated PHMS thicknesses, as on reference sensors coated with vapor-deposited SiO(2). The good adhesive properties of the PHMS to gold allows for the preparation of thin PHMS(ox) layers compatible with SPR. The much smaller roughness at the nanometer scale of the PHMS(ox) surfaces, compared to standard vapor-deposited SiO(2)-coated sensors, makes them advantageous for AFM and optical experiments and promising for patterning. To benefit optical experiments with the PHMS(ox) surfaces, it was also investigated how the PHMS film thickness influences the SPR and reflectometry responses upon SLB formation.