In nature, supramolecular, light harvesting complexes initiate the photosynthetic energy collection process at high quantum efficiencies. In this study, the distinctive antenna structure, derived from the filamentous, green bacterium Chloroflexus aurantiacus—the chlorosome—is assessed for potential exploitation in novel, biohybrid, optoelectronic devices. Chlorosomes are nanoscaled 'bags' of photosensitive pigments that efficiently harvest specific wavelengths of the light spectrum. It is hypothesized that isolated chlorosomes are capable of direct, photoelectronic energy transfer at the electrochemical interface. In this dissertation, chlorosomes at engineered interfaces are extensively characterized for the first time using various bioelectrochemical techniques in a customized electrochemical platform. Electrochemical cells with chlorosomes in solution are shown to change their interfacial charge storage capacities in a light intensity based, dose-dependent manner. In addition, it is shown that chlorosomes that are closest to the working electrode directly contribute a photocurrent in graphite-based electrochemical cells (∼10 nA).

In order to rationally devise a chlorosome-based photosystem, a versatile covalent immobilization strategy to stably and functionally immobilize chlorosomes has been developed. The energy transfer capabilities of immobilized chlorosomes are evaluated using various biophotonic tools. Selected spectroscopic and microscopic characterization methods verify that programmed assemblies of immobilized chlorosomes maintained their biophotonic functionality. Additionally, chlorosomes that are covalently immobilized on indium tin oxide (ITO) substrates are shown to modulate the photocurrent at the interface in a light intensity dependent manner. In fact, chlorosomes in ITO-based electrochemical cells have ∼15-20 times-enhanced photocurrents compared to those that are based on graphite. The results of this research lay the foundation for a unique, bioinspired device that has wide applications, ranging from novel biohybrid solar cell technology to emerging biomedical applications such as retinal prosthetics.