The deposition of Langmuir-Blodgett films containing purple membrane on lipid- and paraffin-impregnated filters

Abstract

Langmuir-Blodgett films containing the light-driven proton pump, bacteriorhodopsin, in the form of purple membrane were deposited onto cellulose ester filters previously impregnated with hexadecane and soya lecithin. The effect of the K +-selective ionophore, valinomycin, on the photopotential generated across these combined films was examined. A simple equivalent electrical circuit was developed in order that the potential of this system as a light-driven ion exchanger might be evaluated. A major rearrangement of the Langmuir-Blodgett film occurred on deposition onto the filters, removing one of the attractions of these films in this application: their multilayer character. The equivalent circuit analysis of the apparent K +H + exchange indicates that the film rearrangements may be similar to the process of lipid rearrangement that occurs when liposomes are fused to a filter.