A COMPARATIVE-STUDY OF PLANAR LIPID-MEMBRANES FORMED BY MONTAL-MUELLER AND MUELLER-RUDIN TECHNIQUES

Planar phospholipid bilayer membranes formed by two techniques, Montal -Mueller and Mueller-Rudin, were compared in order to determine the di fferences between these two types of BLM. The specific capacitance and the morphology of membranes formed from different lipid/solvent combi nations were examined using a ramp of voltage and high resolution inte rference contrast and fluorescence microscopy. It was found that the s pecific capacitance depends more upon the choice of lipids and hydroca rbons used for membrane formation than upon the method of formation. F or diphytanoyl-phosphocholine membranes, capacitance increases with th e increase in molecular weight of the hydrocarbon used either for hole pretreatment or for making a membrane forming solution. For phosphati dylethanolamine membranes. No differences were found in the morphology of membranes formed using these techniques. Both led to membranes hav ing tort, and the membranes often contained lenses and/or linear struc tures. Examination of these structures in membranes formed with the ad dition of fluorescent lipid indicates that they contain substantial am ount of lipid.