Polymer-stabilized phospholipid vesicles with a controllable, pH-dependent disassembly mechanism.

In this letter, we report a facile method to prepare robust phospholipid vesicles using commonly available phospholipids that are stabilized via the formation of an interpenetrating, acid-labile, cross-linked polymer network that imparts a site for controlled polymer destabilization and subsequent vesicle degradation. The polymer network was formed in the inner lamella of the phospholipid bilayer using 2,2-di(methacryloyloxy-1-ethoxy)propane (DMOEP) and butyl methacrylate (BMA). Upon exposure to acidic conditions, the highly cross-linked polymer network was partially converted to smaller linear polymers, resulting in substantially reduced vesicle stability upon exposure to chemical and physical insults. Isolated polymers had pH-dependent-solubility in THF. Transmission electron microscopy and dynamic light scattering revealed time-dependent enhanced vesicle stability in high concentrations of surfactant and vacuum conditions at elevated pH, whereas exposure to acidic pH rapidly decreased the vesicle stability, with complete destabilization observed in less than 24 h. The resultant transiently stabilized vesicles may prove useful for enhanced drug delivery and chemical sensing applications and allow for improved physiological clearance.