Photothermally triggered lipid bilayer phase transition and drug release from gold nanorod and indocyanine green encapsulated liposomes

In light-Activated liposomal drug deliver systems (DDSs), the light sensitivity can be obtained by photothermal agent that converts light energy into heat. Exces heat increases the drug permeability of the lipid bilayer, an drug is released as a result. In this work, two near-I responsive photothermal agents in a model drug deliver system are studied: either gold nanorods (GNRs) encapsulate inside the liposomes or indocyanine green (ICG) embedde into the lipid bilayer. The liposome system is exposed to light and the heating effect is studied with fluorescent thermometers laurdan and CdSe quantum dots (QDs). Bot photothermal agents are shown to convert light into heat in an extent to cause a phase transition in the surrounding lipi bilayer. This phase transition is also proven with laurdan generalized polarization (GP). In addition to the heating results, w show that the model drug (calcein) is released from the liposomal cavity with both photothermal agents when the light power i sufficient to cause a phase transition in the lipid bilayer.