Liposomes bearing poly(hydroxyethyl acrylate-co-ethyl vinyl sulfide) and indocyanine green and their temperature, oxidation, and near infrared-responsive release property.

Liposomes are widely used for smart delivery due to their biodegradability and biocompatibility. Recently, liposomes have been developed to respond to dual and multi-stimuli. This development leads to the potential for superior in vitro and in vivo drug delivery in the future. In this study, egg PC liposomes responsive to temperature, oxidation, and NIR irradiation were prepared by modifying the liposomal membranes with poly(hydroxyethyl acrylate-co-ethyl vinyl sulfide) (P(HEA-co-EVS)) and including indocyanine green (ICG) in the liposomes.The copolymer was found to exhibit a lower critical solution temperature (LCST) and it was oxidizable and surface-active.On the TEM photos of the liposomes, multi-lamellar vesicles were found and the size was in accordance with the hydrodynamic diameter. The liposomes released their payload in response to H2O2 concentration possibly because the EVS was oxidized by the oxidizing agent. The liposome exhibited a temperature-responsive release possibly due to the thermal contraction of the copolymer chains.In addition, the release was triggered when a near-infrared(NIR) laser was irradiated to the liposome suspensions. Under NIR irradiation, the photosensitizer (i.e. ICG) can generate heat and reactive oxygen species, which, in turn, would induce the conformational and polarity change of the polymer chains, leading to a release. [ABSTRACT FROM AUTHOR]