Fabrication of novel photosystem I–gold nanoparticle hybrids and their photocurrent enhancement

We have first prepared a novel bio-nanohybrid electrode consisting of a photosynthetic protein complex, photosystem I (PSI), and gold nanoparticles, and have measured their photocurrent generation properties. The hybrid electrode was fabricated by three steps: sedimentation of gold nanoparticles on a planar gold substrate, followed by modification with 3-mercapto-1-propanesulfonic acid by gold–sulfur self-assembling, and finally modification with PSI by electrostatic adsorption. Even though PSI is one of the proteins and is much larger than usual organic dyes for photocurrent generation, we have. succeeded in constructing PSI–gold nanoparticle hybrid electrodes, and in obtaining substantially greater photocurrent responses from PSI as compared with the corresponding planar electrode system.