Photodynamic PEGylation Coated Prodrug-Nanoassemblies for Core-Shell Synergistic Chemo-Photodynamic Therapy

Abstract

Combination of chemotherapy with photodynamic therapy (PDT) holds promising applications in cancer therapy. However, co-encapsulation of chemotherapeutic agents and photosensitizers (PS) into the conventional nanocarriers suffers from inefficient co-loading and aggregation-caused quenching (ACQ) effect of PS trapped in dense carrier materials. Herein, we report a light-activatable photodynamic PEGylation-coated prodrug-nanoplatform for core-shell synergistic chemo-photodynamic therapy. A novel photodynamic polymer is rationally designed and synthesized by conjugating pyropheophorbide a (PPa) to polyethylene glycol 2000 (PEG2k). PPa is used as the hydrophobic and photodynamic moiety of the amphipathic PPa-PEG2k polymer. Then, a core-shell nanoassemblies is prepared, with an inner core of a reactive oxygen species (ROS)-responsive oleate prodrug of paclitaxel (PTX) and an outer layer of PPa-PEG2k. PPa-PEG2k serves both for PEGylation modification and PDT. Instead of being trapped in the inner core, PPa in the outer PPa-PEG2k layer significantly alleviates the ACQ effect. Under laser irradiation, ROS generated by PPa-PEG2k is not only used for PDT, but also synergistically promotes PTX release in combination with the endogenous ROS overproduced in tumor cells. The photodynamic PEGylation coated nanoassemblies demonstrated synergistic antitumor activity in vivo. Such a unique nanoplatform, with an inner chemotherapeutic core and an outer photodynamic PEGylation shell, provides a new strategy for synergistic chemo-photodynamic therapy.