Photonic interactions in biomolecular micro and nano systems

The focus of this talk is the presentation of data with novel electronic devices that are comprised of biological components. We have extracted Photosystem I reaction centers from spinach leaves. Using the combined techniques of tapping-mode atomic force and scanning surface probe microscopies, we have demonstrated that PSI retains its molecular photovoltaic properties. PSI has been used to impart photoactivity to tissue cultures of retinoblastoma cells. Photoactive mammalian cells are novel hybrid biological structures that may have application in the field of artificial sight. We are also interested in the general problems of biomimetic photosynthesis, molecular "wiring" and the interfacial properties of protein-metal interfaces. Metallic platinum can be photoprecipitated at the point of electron emergence from the PSI reaction center in such a way that electric contact is made between protein and metal nanocatalyst. If platinization is performed on the stromal side of thylakoid membranes, it's possible to observe the simultaneous photoevolution of hydrogen and oxygen. This biomimetic reaction is a direct analog of natural photosynthesis in which the energy-rich product is molecular hydrogen rather than a carbon dioxide fixation compound. We have demonstrated that plastocyanin and PSI can be molecularly wired to enhance electron transfer between these two biomolecular electron transport proteins. In addition, we have performed spectroscopy and photochemistry of spinach PSI entrapped and stabilized in a hybrid organosilicate glass