Liposomes were initially referred to as near crystalline mesophase, consisting of single or multiple spherical vesicles, primarily composed of phospholipids from plants or animals. When phospholipids are dispersed in aqueous media, they spontaneously form closed vesicles with concentric lipid bilayer membranes and hydrophilic cores. Liposomes have a spontaneously formed closed spherical structure composed of one or more concentric curved lipid bilayers and cholesterol, with sizes ranging from 20nm to a few micrometers. Due to the amphiphilic nature of lipids in liposomes, they can serve as candidate carriers for drug delivery. When encountering an aqueous environment, the amphiphilic substances first disperse, and when they exceed a certain concentration, aggregation occurs by increasing the entropy of the system.
