1. Nanoscience: Single Atom Electrochemistry + High Entropy Alloy Nanoparticles
2. Single Cell Biology
Ever since Democritus' time, the idea of a single atom (Greek 'atomos' = indivisible) has propagated throughout science. Millenia later in our lab, we regularly measure reactivity of single, isolated atoms and small clusters using attoliter (one liter divided into a billion parts... and those parts divided into a billion parts!) water droplets. Our lab has also developed a new method of synthesizing high entropy alloy nanoparticles, and we are using these techniques to design multifunctional electrocatalysts for applications to energy storage and conversion devices.
Currently, the redox state of single, living cells is accessible only by fluorescence microscopy. Upon oxidation or reduction of key amino acids associated with fluorescent redox proteins, conformation changes cause differences in emission wavelength. Thus, the relative amounts of oxidized and reduced protein can be used to gauge the redox environment of a cell. Similarly, the redox state can be studied if the emitting protein is specific to a certain metabolite species, as has previously been shown (Cambronne et. al., 2016, Science) for cytosolic NAD+. Unfortunately, these experiments cannot be performed in the absence of light. It has been shown that the act of shining light on a cell can have a deleterious effect on metabolism. For instance, cytochrome C absorbs blue light and degrades, decreasing mitochondrial respiration with time. We are developing nanoelectrode probes to study how wavelength and intensity of light affects cell metabolism at the single cell level. Furthermore, we are fabricating metabolite-specific nanoelectrodes. This research can be used across a vast range of cell lines to study variations in metabolism across different areas of human disease.