Analysis of RNA-Mediated Materials Synthesis Using Magnetic Selection

The products that result from the mediation of imidazole-modified RNA (imRNA) using FeCl₂, CoCl₂, NaCl, and KCl as starting materials for nanoparticle synthesis are studied using high resolution transmission electron microscopy (HRTEM), electron energy loss spectroscopy (EELS), X-ray photoelectron spectroscopy (XPS), and superconducting quantum interference device (SQUID) magnetometry. The combination of analytical methods shows that, although elemental Fe and O may be present in some samples, the majority of the samples consist of NaCl and KCl, which can form nanoparticle structures under the conditions of the experiment. The observed result is consistent with the formation of diamagnetic particles or formation of magnetic material at a concentration below the limit of detection by any of the analytical methods used. We find no evidence for iron oxide nanoparticle formation under the conditions of the selection. On the basis of the analysis, it appears that ³²P radiolabeled imRNA was detected in previously presented assays only because imRNA binds to salt particles or possibly to iron oxide particles, which are not observed directly because their quantity is below the detection limit of EELS, XPS, or SQUID measurements. The role of magnetic field selection is examined critically on the basis of the physical measurements as part of the set of conditions required to prove imRNA-mediation.