(729f) Construction of Biomimetic Photocathodes Using Photosystem I-Proteoliposomes Supported on Substrates

This work focuses on utilizing the cyanobacterial photosystem I (PSI) from Thermosynechocoocus Elongatus for integration into organic/inorganic interfaces in bio-hybrid devices that mediate photo-electrochemical energy conversions for electricity and/or solar fuel production. Here, we report on the successful PSI confinement in synthetic biomimetic membrane scaffolds (PSI-proteoliposome formation) and successful assembly of PSI-proteoliposomes on suitable SAM substrates for light-to-current conversion applications. For this purpose, a facile yet elegant method for detergent-mediated reconstitution of proteoliposomes is introduced and consequently gold substrates have been modified with SAMs with different chemistries to achieve a systematic assembly of oriented and functional PSI-proteoliposomes. Our results show a cathodic photocurrent response and functionality of the biohybrid system upon illumination. Detailed electrochemical measurements and force spectroscopy measurements verify that the photocurrent generation can clearly be attributed to a functional PSI-proteoliposomes on the substrate interface. The significant observation here is the enhanced photo current generation from PSI complexes under liposome confinements as compared to that produced from dense monolayer of individual PSI on SAM substrates using an equivalent concentration of PSI. In turn, the aforementioned studies provide valuable insight into easy incorporation of membrane protein-lipid complexes into novel bio-hybrid devices.