Light-induced electrical response of chromatophore film in a semi-wet photocell with an agar layer containing an electron mediator

Light-induced electrical response (open-circuit voltage and short-circuit current) was measured for chromatophore films in a semi-wet photocell. Chromatophores, which are membrane fragments of photosynthetic organelle, were isolated from a photosynthetic bacterium, Rhodopseudomonas viridis, and were immobilized on a substrate electrode by an electrodeposition method. The semi-wet photocell was chromatophore film layer and an agar layer containing an electron mediator, K-4[Fe(CN)(6)], sandwiched between two ITO electrodes. The photoresponses were enhanced by a factor of 1000 when an electron mediator added to the chromatophore layer: the open-circuit voltage and the short-circuit current were 120 mV and 450 mu A cm(-2), respectively. (C) 1997 Elsevier Science S.A.