Knapp Research Group

Chemistry Department

Increasing the efficiency of dye-sensitized solar cells is crucial to harvesting the sun's energy for our use.  Solar cells of the future will ideally combine the efficient electron/hole separation of semiconductors within a self-assembled architecture. We are collaborating with other groups to explore hybrid nanoparticle/protein systems as an approach to developing self-assembled structures with protein-based charge-transport.  We are using surface-functionalized nanoparticles to recognize redox proteins to explore hybrid systems which support charge transfer, with the ultimate goal being the creation of "green" systems for solar cell applications.

We have focused our attention on developing nanoparticle hybrids with cytochrome c (Cyt c) and cytochrome c peroxidase (CcP) due to their facile spectroscopy, the simple chemistry of reducing H₂O₂, and their well-characterized binding interfaces.  We have shown that polymeric and gold nanoparticles with simple functionalities interrupt the Cc:CcP electron transfer by selectively binding to the protein surface, and showed that gold nanoparticles functionalized with single amino-acids bind to Cyt c on the same surfaces as natural redox partners.  We recently mapped the surface of Cyt c which binds to different nanoparticles through the use of amide exchange methods (amide HDX).  This work showed that the functionality of the nanoparticle led to different binding modes on Cyt c, and implicates a combination of coulombics and hydrophobicity in determing facial specificity for binding.  We are extending this work to correlate redox reactivity with binding mode in both Cyt c and CcP.