Studies on Luminescent Gold and Platinum Nanoclusters for Biological Sensing and Catalysis

Covington, Richard (2019) Studies on Luminescent Gold and Platinum Nanoclusters for Biological Sensing and Catalysis. Undergraduate thesis, under the direction of Saumen Chakraborty from Chemistry & Biochemistry, The University of Mississippi.

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Abstract

Nanoclusters are small nanoparticles that usually range around a micrometer in diameter. Gold Nanoclusters are known for their unique size and surface qualities and do not share metallic properties with nanoparticles or their respective bulk material. Some metal nanoclusters show high fluorescence and can be synthesized with protein mediation. Nanocluster formation depends on a number of variables, including temperature, pH, and type of reducing agent. This experiment was done to begin to understand how these variables may affect synthesis and what exactly they are. Pure Wild Type CSP-1 protein was induced, transformed, and purified in order to mediate gold and platinum nanocluster synthesis in a variety of different situations. When mixed in solution, the free Au3+ ions from HAuCl4 form clusters by attaching to the many cysteine side chains of the protein. Data was collected showing that in a neutral pH, using a solution of 50mM Tris and 150mM NaCl, highly fluorescent gold nanoclusters formed. These nanoclusters synthesized using 1M sodium hydroxide reducing agent showed the brightest fluorescence, a bright red-orange. Nanocluster formation in this experiment was confirmed through a matrix assisted laser desorption/ionization test. It was found that in the samples showing fluorescence, gold nanoclusters could be observed with a mass of 4kDa. This means that a nanocluster formed with around 20 Au atoms.

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