Behaviors of liposomes in a thermo-responsive poly(N-isopropylacrylamide) hydrogel

Liposome-embedded hydrogels have been widely used for controlled drug release. In this work, by embedding egg phosphatidylcholine (EPC) liposome into a poly(N-isopropylacrylamide) (PNIPAm) hydrogel via chemical cross-linking, we systemically studied the physical interactions between the liposome and hydrogel matrix, as well as the release mechanism of the encapsulated content in the liposome at varying temperatures. It was found that the confinement of the network and the hydrophobic interactions between the liposome and PNIPAm determined the integrity of the liposome and, more importantly, the release profile of the encapsulated content, such as calcein. This liposome-embedded stimuli-responsive system is suitable for the delivery of mixed drugs with different release profiles, and easily achieves on-demand release.