Nanoscale Biological Engineering Laboratory

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Interfacing enzymes on inorganic surfaces / electrodes

Glucose oxidase enzyme

One fun project that we are working on right now is attempting to anchor enzymes onto variable-lengh conductive nanowires. We beleive that if we are successful, we will be able to significantly enhance charge transport between the biomolecule and the electrode. This will be a significant step towards developing more effective fuel cells and biosensors.

We conjecture that it is possible to maximize the surface utilization by allowing the electrode to access multiple active sites present in enzymes (such as lactate dehydrogenase - LDH) using ligands that are flexible and long enough. If we are able to do this without circumventing the conductive properties of the molecular wires, it will be possible to enhance the effectiveness of sensors and fuel cells that use these electrodes.

It is surmised that the electron transfer properties between an enzyme's active site and the metal electrode can be significantly improved by substituting conventionally used cystamine (or mercapto propane sulfonate-MPS) type molecules with novel molecules. The electronic structures of cystamine and MPS molecules that are used to attach biomolecules to metal surfaces are not quite conducive for electron transport due to meager availability of mobile electrons in the conductive band. As a result, the internal resistance of electrodes developed based on these interfacing agents is high. In contrast, recent studies have identified molecules that are orders of magnitude more conductive than cystamine or MPS. Our goal is to functionalize one end of such nanowires to attract enzymes and the other end to attach to numerous metal electrodes.

An Example of a fuel cell that was developed using bio-inorganic hybrid catalysts is depicted above. In this particular fuel cell the anode is composed of Pt and glucose oxidase enzyme.