(107b) Invited: Engineering the Protein/Nanomaterial Interface for Biosensors and Biofuel Cells

The optimization of the protein/nanomaterial interface is a critical in the development of bioelectrocatalytic systems such as biosensors and biofuel cells.  We have been developing protein engineering strategies to produce enzymes optimized for performance in these systems.  In this presentation, I will review some recent accomplishments in this endeavor.

One key challenge in producing bioelectrocatalytic systems is the immobilization of enzymes and mediators on an electrode with high density while maximizing activity.  We have developed self-assembling proteinaceous hydrogels for this purpose, and we can incorporate mediators in this system as needed.  We have recently expanded this approach to make a biocatalytic hydrogel comprised of a 3-enzyme metabolic network that can oxidize methanol to CO₂.

Some enzymes require soluble cofactors, and this can limit performance.  We have recently engineered an alcohol dehydrogenase to have both altered substrate and cofactor specificities.  Now we have explored its ability to utilize a smaller non-natural cofactor and we have demonstrated the advantages of using artificial cofactors on biofuel cell performance.

In some applications, mediatorless systems are preferred, and we have explored the appending of nanomaterials on enzymes to serve as redox relays.  We have been able to functionalize glucose oxidase with a gold nanoparticle and demonstrated direct electron transfer with this system.

We are currently exploring protein assemblies for improved biocatalytic performance. We are reverse engineering a classic metabolon structure from the mammalian TCA cycle.  We are also using computational protein design to create new self-assembling enzymatic complexes.  The most recent results of these new projects will also be discussed.