Near-Infrared-Light-Responsive Nanocomposites of Cell Membrane Mimetic Copolymers and Upconverting Nanoparticles for On-Demand Drug Release

A number of well-controlled amphiphilic copolymers of poly(2-methacryloyloxyethyl phosphorylcholine-co-azobenzene methacrylamide) (PMA), carrying both cell outer membrane mimetic phosphorylcholine zwitFVterion groups and ultraviolet (UV)-sensitive hydrophobic azobenzene units, were prepared by reversible addition–fragmentation chain-transfer polymerization and applied to fabricate a novel UV/near-infrared (NIR) dual-responsive cell membrane mimetic micelle through the encapsulation of upconversion nanoparticles (UCNPs) into PMA micelles. The diameter of the UCNPs@PMA micelles could be well-controlled by adjusting the feeding ratio between UCNPs and PMA. The obtained UCNPs@PMA micelles displayed a controllable drug-release performance by tuning the duration of UV/NIR-light irradiation. Furthermore, the UCNPs@PMA micelles showed enhanced biocompatibility and a remarkable NIR-triggered therapeutic effect. Interestingly, doxorubicin-loaded UCNPs@PMA micelles showed pH-responsive drug release and much higher cytotoxicity of the tumor cell than of the normal cell after NIR laser irradiation. Therefore, the UCNPs@PMA micelles may serve as a powerful on-demand chemotherapy platform in cancer therapy via the NIR-light-triggered drug-release ability.