Over the past 10 years, researchers have been investigating the prospects of solar energy devices that utilize Photosystem I (PSI), an incredibly efficient nanoscale membrane protein complex responsible in part for the harvesting of solar light energy by photosynthetic organisms including plants and cyanobacteria. These biosolar cells consist of layers of PSI deposited on a conducting or semiconducting electrode, which produces electrical current under light exposure through a series of redox reactions. Because PSI transfers current unidirectionally, orientation is a major concern during the fabrication process: deposition of protein parallel to the plane of the electrode will not increase photocurrent density, while inverted deposition will reverse the direction of electron transfer and electrical current, leading to an overall decrease in photocurrent density from the optimum.<br/><br/>In this work, PSI was asymmetrically functionalized with thiols to enable orientationally-selective self-assembly onto gold electrodes. Thylakoids were isolated from spinach leaves, with PSI still in the thylakoid membrane. Exposed stromal lysine residues were targeted for thiol functionalization via reaction with Traut’s reagent (2-iminothiolane). Thiol-modified PSI on Au exhibited a three-fold increase in photocurrent density over unmodified PSI.

Asymmetric chemical modification of Photosystem I enabling orientationally-selective deposition on gold electrodes

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.