Biohybrid Photoelectrochemical Nanoengineered Interfaces
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1191-OO03-19
Biohybrid Photoelectrochemical Nanoengineered Interfaces
Arati Sridharan, Jit Muthuswamy, and Vincent B. Pizziconi Harrington Department of Bioengineering, Arizona State University, MB 9709 Tempe, AZ 85287, U.S.A.
ABSTRACT Incorporation of biophotonic components in artificial devices is an emerging trend in exploring biomimetic approaches for green technologies. In this study, highly efficient, nanoscaled light antenna structures from green photosynthetic bacteria, known as chlorosomes, comprised of bacteriochlorophyll-c pigment arrays that are stable in aqueous environments are studied in an electrochemical environment for their photoelectrogenic capacity. Biohybrid electrochemical cells containing chlorosomes coupled to the native bacterial photosynthetic apparatus have a higher dark charge storage density (at least 10-fold) than electrochemical cells with decoupled chlorosomes. Nevertheless, upon light stimulation, the charge storage density, also known as charge injection capacity, for both electrochemical systems increased the charge stored near the electrode. Decoupled chlorosome-based systems showed a light-intensity dosedependent response, reaching a maximum change of ~300 nC/cm2 at near sunlight intensities (~80-100mW/cm2). Chronoamperometric studies under light stimulation conditions confirmed the photo-induced effect. Current studies are focused on optimization of the electrode/chlorosome interfacial properties across various heterogeneous interfaces. Successful implementation of harvesting photo-energy using the chlorosome or its derivatives may lead to substantial innovations in current biophotonic technologies, such as biofuel cells and retinal prosthetics.
INTRODUCTION A key aspect of current lab-on-chip and biotechnology instruments occurs at the interface between the biological transducing element and the electrode. Interfacial energy transfer from a biomaterial to the artificial electrode system is difficult to characterize and often involves building the entire device to assess performance. In this study, a design parameter known as the charge storage density (CSD) is used to assess heterogeneous, biohybrid interfaces for potential optoelectronic devices. CSDs are typically used in the neuroscience and biomedical fields to assess the charge stored near the electrode/electrolyte interface in order to establish safe neurostimulation parameters [1,2]. As a novel extension of the concept, light-stimulated effects on photosynthetic materials derived from the green bacteria, Chloroflexus aurantiacus, are investigated in an electrochemical manner. In particular, the main light-harvesting structure of the green bacterium, known as the chlorosome, is studied for its photoenergy transfer capabilities in the absence of its native photosynthetic machinery. The chlorosome is a unique, nanoscaled structure, which is composed of arrays of self-assembled bacteriochlorophyll-c (BChl c) pigment
molecules enclosed in a lipid monolayer [3]. Its extraordinary, natural properties, such as a 92% quant
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