The Fluidization Effect of a Bilayer Membrane on a Fatty Acid Vesicle by a Detergent

A bicelle, which is a bilayer molecular assembly, can be prepared by fluidizing a vesicle in the presence of a detergent. We investigated the effect of two different detergents, 3-[(3-cholamidopropyl)dimethylammonio]-2-hydroxypropane sulfonate (CHAPSO) and Triton X-100 (TX), on the formation of a bicelle from a vesicle containing oleic acid (OA) and the detergent molecules. The fluidization effect of the detergent was evaluated using the membrane packing density, which we measured using the fluorescent probe method with Laurdan, in conjunction with transmission electron microscopy to examine the morphology of the prepared bilayer molecular assemblies. As a result, it was discovered that the OA/CHAPSO system could form a heterogeneous phase with the highest packing density, implying that CHAPSO was the better detergent for a bicelle preparation, whereas the OA/TX system formed a disordered phase with the lowest packing density.