II . 1 . 2 Nanoscale Electrochemical Probes for Monitoring Bioconversion Hydrogen

Introduction The economic production of hydrogen remains one of the key issues for realizing the hydrogen economy. In response to this challenge, Professors Swartz and Spormann, are pursuing biological production of hydrogen as part of the GCEP hydrogen initiative. Our team works with Professors Swartz and Spormann to develop nano scale sensors to better understand the electro-chemistry of hydrogen production via bio-energy conversion. The sensors are designed to measure reduction-oxidation reactions, electron transfer reactions, and the broader kinetics of biochemical processing within the cell cytosol. The sensors we are pursuing may also be employed to determine membrane potentials across lipid bilayers. Considering the size of the cells we are investigating, which is less than 5 microns, we estimate that the size of the sensors must be at least one order of magnitude smaller. Therefore, we manufactured probes with a diameter of tens to hundreds of nanometers. We are integrating these sensors into a single cell diagnostic platform that is capable of mapping biochemical reactions inside single cells. (A schematic drawing of the experimental set up is shown in Fig.1).