470872 Photo-Electrochemical Characterizations of Photosystem I (PS I) Assembly Under Bio-Mimetic Membrane Confinement

Thursday, November 17, 2016: 1:54 PM
Golden Gate 6 (Hilton San Francisco Union Square)
Hanieh Niroomand, Chemical and Biomolecular Engineering, Sustainble Energy and Education Research Center (SEERC), The University of Tennessee, Knoxville, TN, Dibyendu Mukherjee, Mechanical, Aerospace and Biomedical Engineering, Sustainble Energy and Education Research Center (SEERC), The University of Tennessee, Knoxville, TN and Bamin Khomami, Department of Chemical and Biomolecular Engineering, Material Research and Innovation Laboratory (MRAIL), Knoxville, TN

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.

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