Comb-shaped, temperature-tunable and water-soluble porphyrin-based thermoresponsive copolymer for enhanced photodynamic therapy

- We report a novel comb-like thermo-responsive porphyrin-based copolymer.
- This porphyrin-based copolymer was LCST of between 37 °C and 42 °C, which could aggregate around the target tumor cells.
- The MTT assay of the porphyrin-based copolymer show photodynamic effect to the tumor cells.

A novel comb-shaped porphyrin end-functionalized poly(N-isopropylacrylamide)-b-poly[oligo (ethylene glycol methyl ether methacrylate)] (Por-PNIPAM-b-POEGMA) was synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. Due to the incorporation of hydrophilic POEGMA contents, the copolymer shows the lower critical solution temperatures (LCST) of 37-41.8 °C higher than PNIPAM. Moreover, this copolymer showed efficient singlet oxygen under light irradiation at 650 nm, and the productivity of singlet oxygen was 0.59, which could be used for photodynamic therapy. In addition, the in vitro study indicated that this copolymer showed no significant dark cytotoxicity, while showed apparent photo-toxicity toward HeLa cancer cells under red light irradiation at 650 nm. MTT results indicated that this copolymer with appropriate LCST could be accumulated on locally tumor tissues and killing of cancer cells (Hela), which may be a promising photosensitizer in photodynamic therapy for cancer treatment.