In vivo photodynamic therapy based on Near-Infrared AIE cationic polymers

Abstract

• Cationic AIE polymers synthesized from AIEgen monomers with D-A-D structures. • Quaternary ammonium groups in our AIE-polymers enhance the biocompatibility for PDT. • AIE polymers with absorption maximum near 520 nm and activation by white LED light. • AIE polymers with NIR fluorescence imaging capacity and effective 1 O 2 production. • A metal-free and high atomic-efficiency polymerization method for our AIE polymers. New near-infrared (NIR) photo-responsive polymers with the merits of highly biocompatibility, penetrability and biostability, are highly desirable for cancer photodynamic therapy. Herein, a near-infrared cationic polymers (DCPN-2) featuring aggregation-induced emission (AIE) is synthesized via a ring-opening polymerization to achieve the forceful restriction of intramolecular motion, yielding nanoparticles (NPs) with diameter of about ∼ 200 nm. DCPN-2 exhibits the bright emissions in the NIR region (>650 nm) covering most of visible-light range and effectively generates reactive oxygen species (ROS) under light irradiation. Importantly, the inhibition of tumor growth upon DCPN-2 treatment under light irradiation was demonstrated both in vitro and in vivo. Collectively, this study not only provides potential NIR AIE-polymers for cancer phototheranostics, but also presents a novel strategy of the design of biocompatible photo-responsive polymers for future biomedical applications.