Photoelectric Responses of Lipid Membranes

Thin lipid membranes formed in aqueous solution from chloroform-methanol solutions of α-tocopherol or α-tocopherol plus sphingomyelin or sphingomyelin in decane gave photoelectric responses to μwatt energies of ultraviolet (UV) light of up to 160 mV and 1600 pA. The performance of all membranes was enhanced by placing an iodide solution on one side of the membrane. The location of the iodide solution was important in regard to the response obtained and specific differences were seen with membranes having different compositions. The action and absorption spectra of the membranes were determined, the effect of reversing the light direction ascertained and the current-voltage characteristics of the membranes examined before, after and during exposure to UV radiation. From data obtained it was hypothesized that changes in the membrane induced by UV radiation were an important part of the mechanism leading to the photoelectric effect.