(746d) Systematic Assembly of Photosystem I On Thiol Activated SAM/ Au Substrates for Future Bio-Hybrid Photovoltaic Devices

Photosystem I (PSI), a supra-molecular protein complex, acts like a biological photodiode that charge separates upon exposure to light and is responsible for driving natural photosynthesis mechanism. Effective use of photo-electrochemical activities of PSI for hybrid photovoltaic (PV) device fabrications requires optimal encapsulation of these proteins onto organic/ inorganic substrates. Our results indicate that various experimental parameters alter the surface attachment dynamics of PSI deposited from colloidal aqueous buffer suspensions onto OH-terminated alkanethiolate/Au SAM substrates, thereby resulting in complex structural arrangements which affect the electron transfer and capture pathway of PSI. We present surface topographical, specific adsorption, and electrochemical characterizations of PSI/Au SAM substrates to elucidate the protein-surface interaction kinetics as well as the directional attachment dynamics of PSI to ensure proper photo-activated electronic activities. Our results from dynamic light scattering analysis of the protein suspension in bulk solution phase coupled with TEM, AFM based images and ellipsometry studies also indicate that specific detergents used for PSI suspension in solution phase drive unique surfactant mediated protein-protein interactions which in turn determine the surface morphology of the protein attachment. Our final goal is to enable site-specific homogeneous attachment of directionally aligned PSI onto chemically tailored nano-patterned substrates for future bio-hybrid photovoltaic or bio-electronic devices.