Smart Photothermal-Triggered Bilayer Phase Transition in AuNPs–Liposomes to Release Drug

Novel thermosensitive liposomes with embedded Au nanoparticles (AuNPs) in the liposome bilayer were prepared by a combination method of film build and supercritical CO2 incubation. These AuNPs–liposomes possess AuNPs that are embedded in the bilayer and a drug that is encapsulated in the central aqueous compartment. The AuNPs in the liposomes can strongly absorb light energy and efficiently convert the absorbed energy to heat. The localized heat induces a phase transition in the liposome bilayer and releases the drug. The drug release from the AuNPs–liposomes can be controlled by the irradiation time and AuNPs concentration in the AuNPs–liposomes at room temperature, where the AuNPs function as a nanoswitch for triggering drug release both spatially and temporally. The results suggest that drug release from the AuNPs–liposomes is due to a photothermic effect that induces phase transition of the liposomes rather than destruction of the liposome bilayer.