Award Submission _ Photo-Electrochemical Characterizations of Photosystem I (PS I) Assembly Under Bio-Mimetic Membrane Confinement

The robust structural and photoactive electrochemical properties of Photosystem I (PSI) make it an ideal candidate for incorporation into bio-hybrid photovoltaic devices. However, the first step towards the rational design of such devices require systematic and oriented assembly of PS I at bio-abiotic interfaces via suitable scaffolding. To this end, our goal is to incorporate and assemble individually oriented PS I complexes into synthetic membrane-bound structures that mimic the natural thylakoid membrane housing of PS I. We investigate the photocurrent generation from such organic-inorganic interfaces in membrane bound PS I systems. Detergent-mediated reconstitution of proteoliposomes is analyzed via absorption and fluorescence spectroscopy measurements. Successful immobilization of membrane bound PS I on gold substrates are mediated by the hydrophillic interfaces of self-assembled monolayers (SAMs). To this end, force-distance spectroscopy during atomic force microscopy (AFM) imaging of lipid bilayer membranes on thiolated Au substrates confirm monolayer formation. Furthermore, topography measurements using liquid-AFM techniques confirm the assembly of membrane-bound PS I. Finally, the current work presents photo-electrochemical (PEC) characterizations demonstrating enhanced photocurrent generation from PS I complexes assembled under membrane confinement as compared to their isolated immobilizations on electrodes. In turn, the aforementioned studies provide valuable insight into future incorporation of bio-mimetic membrane bound protein complexes into novel bio-hybrid devices.