Rectified photocurrents from purple membrane Langmuir-Blodgett films at the electrode-electrolyte interface

Abstract Langmuir-Blodgett (LB) films of the halobacterial purple membrane (PM) were formed on an SnO2 electrode. A photoelectrochemical cell was constructed in which the PM-coated SnO2 electrode in contact with an aqueous electrolyte contributes to light-to-current conversion under regulation of the electrode potential. Visible light irradiation to the PM electrode caused rectified cathodic photocurrents with the action spectrum coinciding with the optical absorption of bacteriorhodopsin (bR). The photocurrent significantly depended on the electrode potential and pH of the electrolyte. The response time of the photocurrent (less than 300 μs) agrees with the rate of the proton transfer in the photochemical cycle of bR. The electrochemical investigation showed that charge displacement (or proton transfer) in the bR molecules accommodated in an aqueous electrolyte can be effectively converted to electric currents under potentiostatic regulation of the PM electrode.

[1]  H Takei,et al.  Implementing receptive fields with excitatory and inhibitory optoelectrical responses of bacteriorhodopsin films. , 1991, Applied optics.

[2]  A. V. Maximychev,et al.  Oriented purple-membrane films as a probe for studies of the mechanism of bacteriorhodopsin functioning. II. Photoelectric processes , 1987 .

[3]  Agner Fog,et al.  Electronic semiconducting oxides as pH sensors , 1984 .

[4]  H. Sasabe,et al.  Photovoltaic properties of purple membrane Langmuir-Blodgett films , 1988 .

[5]  Su-yi Liu,et al.  Light-induced currents from oriented purple membrane: I. Correlation of the microsecond component (B2) with the L-M photocycle transition. , 1990, Biophysical journal.

[6]  T. Miyasaka,et al.  Quantum Conversion and Image Detection by a Bacteriorhodopsin-Based Artificial Photoreceptor , 1992, Science.

[7]  Albert F. Lawrence,et al.  A Spectroscopic, Photocalorimetric, and Theoretical Investigation of the Quantum Efficiency of the Primary Event in Bacteriorhodopsin , 1989 .

[8]  D. Oesterhelt,et al.  Isolation of the cell membrane of Halobacterium halobium and its fractionation into red and purple membrane. , 1974, Methods in enzymology.

[9]  Tsutomu Miyasaka,et al.  A novel photoreactive amphiphile of nitrophenylazide for immobilization of bioactive proteins , 1989 .

[10]  F. Boucher,et al.  On the action spectrum of the photoelectric transients of bacteriorhodopsin in solid-state films , 1991 .

[11]  Tsutomu Miyasaka,et al.  Photoelectrochemical Behavior of Purple Membrane Langmuir-Blodgett Films at the Electrode-Electrolyte Interface. , 1991 .