Oxidation of phosphatidylcholine membranes by singlet oxygen generated in the gas phase.

Singlet-oxygen (1O2) was generated in the gas phase by heterogeneous photosensitization and bubbled into suspensions of phosphatidylcholine (PC) liposomes. Lipid peroxidation and membrane lysis were observed, and were dependent on the 1O2 concentration and the degree of unsaturation of the liposome. An analysis based on large target diffusion theory indicates that approximately 5000, 2800, and 1600 interactions were required for the lysis of large dioleoylPC, dilinoleoylPC and dilinolenoylPC liposomes, respectively.