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Ionizing radiation, which includes X-rays and gamma rays, is used in a variety of different applications, including in human health. However, high levels of exposure can result in significant morbidity and mortality in humans. Molecular and nanoscale systems that can detect different levels of ionizing radiation can ultimately lead to effective sensing platforms for a variety of applications. In the current work, we describe the use of polypeptide-templated formation of bimetallic metal nanoparticles with potential applications as a colorimetric reporter of elevated levels of ionizing radiation typically used in blood irradiation. Cysteine-containing elastin-like polypeptides were employed together with reducing agents in order to engender radiation-facilitated formation of bimetallic gold–silver bimetallic nanoparticles from a mixture of their respective metal salts. This formation of colored nanoparticle dispersions from colorless metal salt solutions acted as a visual reporter of ionizing radiation in the dose range of 25–100 Gy. Nanoparticles were characterized using UV–visible spectroscopy, transmission electron microscopy, elemental analyses and dynamic light scattering. Our results indicate that polypeptide-bimetallic nanoparticle systems may be attractive reporters of elevated levels of ionizing radiation.

This study was based on the hypothesis that spatial–temporal characterization of contaminant-affected redox gradients in a quiescent system could be measured by microbial potentiometric sensor (MPS) arrays incorporated in large, natural biofilm networks. Two experimental chambers, each containing at least 48 equidistantly located MPS electrodes, were fabricated to examine reproducibility of the patterns. The MPS electrodes were exposed to biofilm growth conditions by introducing high dissolved organic carbon (DOC) and dechlorinated tap water at the bottom of the experimental chamber; and the spatial–temporal changes in the MPS array signals were recorded, which showed that signal trends were correlated to the induced changes in DOC. The results indicated that MPS arrays measured the spatial–temporal changes in the aqueous solution caused by an influx of carbon rich water, which could not be detected by conventional oxidation-reduction potential (ORP) electrodes. Interestingly, the experiments conducted over long time periods revealed unusual behaviors like electrical signaling and possible potentiometrically driven communication within the biofilm. These observed behaviors suggest that biofilms may create a large network through which communication signals can be generated and propagated by inducing changes in electric potentials similar to a sophisticated electronic device.

MEMS research has been carried out through industry-university (Tohoku) collaboration for practical applications. Sophisticated devices such as electrostatically levitated rotational gyroscope, MEMS relay for wafer level packaging, array MEMS including multi-probe data storage and multi-column electron beam lithography system, small diameter fiber optic pressure sensor and SiC micro structure for glass press molding, have been developed. Electrical feedthroughs in glass play important role in the wafer level packaging and array MEMS. Materials such as conductive polymer for recording media, carbon nanotube for electron field emitter, SiC for harsh environment are used in these MEMS because of their unique features.