Enhanced photodynamic therapy based on an amphiphilic branched copolymer with pendant vinyl groups for simultaneous GSH depletion and Ce6 release

Photodynamic therapy would suffer from low efficiency in the cancer treatment process if the reactive oxygen species (ROS) generated from a photosensitizer (PS) were reduced by intracellular glutathione (GSH). To overcome this limitation, in this work, we developed an amphiphilic branched copolymer with pendant vinyl groups, and it self-assembled with chlorin e6 (Ce6) into nanoparticles to fabricate a GSH-reaction response drug delivery system. The vinyl groups in the hydrophobic core of the nanoparticles were reacted with GSH by a thio-ene click reaction to release Ce6; simultaneously, the level of GSH decreased for enhanced PDT. Both in vitro and in vivo studies demonstrated that remarkable PDT efficacy for the nanosystem can be achieved.