Combination of PEG-b-PAA Carrier and Efficient Cationic Photosensitizers for Photodynamic Therapy.

Photodynamic therapy (PDT) is recognized to be a promising strategy for anticancer treatment. Considering the progressive application of PDT in clinical trials, highly efficient photosensitizers (PSs) are in strong demand. Aggregation-induced emission (AIE) based PSs are promising phototheranostic materials for tumor imaging and PDT due to their high fluorescence and photosensitizing efficiency. Herein, a PS, TPA-2BCP with AIE characteristics is developed by adopting an acceptor-π-donor-π-acceptor (A-π-D-π-A) structure. However, the accumulation of ionic PSs in the tumor is poor due to non-specific interactions with bio-molecules. Therefore, we use a carboxyl-rich polymer material, polyacrylate polyethylene glycol block copolymer (PEG-b-PAA) to encapsulate the cationic PSs into nanoparticles through ionic interactions. The cationic groups are blocked and the generated PS nanoparticles can accumulate well in the tumor site in vivo. Meanwhile, the photosensitizing efficiency of the PS is further enhanced in the nanoparticle format. The tumor growth can be obviously inhibited under 530 nm laser irradiation, demonstrating its potential application in antitumor PDT.