Monolayers and Langmuir-Blodgett films of photosystem I on various subphase surfaces

Monolayers of a pigment-protein complex, photosystem I (PS I), were investigated on the NaCl, CaCl2, and two kinds of cationic polyelectrolyte subphase surfaces. The monolayers were transferred onto hydrophobic substrate surfaces by a horizontal lifting technique. Both the in situ UV-vis spectra at the air-water interface and the spectra of the transferred Langmuir-Blodgett (LB) films were similar to the spectrum of PS I in buffer solution. Cyclic voltammogram measurement of a PS I/poly(viologen) complex LB film modified electrode showed well reversible redox waves of viologens, which indicated that the film may be useful for the development of a biounit to mimic the photoinduced electron transfer process in the photosynthetic system.