Objective To prepare a novel photosensitive nanoparticle and to evaluate its physicochemical properties, and effect on the efficacy of photodynamic therapy.

Methods 5,15-dibromo-10,20-diphenylporphine (DBN), tetrafluoroterephthalonitrile (TFN), and the amphiphilic polymer methoxy-polyethylene glycol-distearoylphosphatidylethanolamine (DSPE-MPEG2000, PEG) were dissolved in tetrahydrofuran (THF) by co-precipitation method to prepare novel photosensitive nanoparticles, named DBN/TFN@PEG. The physicochemical properties of DBN/TFN@PEG were characterized. Both novel and conventional nanoparticles were continuously irradiated with a 660 nm laser, and the fluorescence intensity of nanoparticles, representing reactive oxygen species (ROS) production levels, was measured using a fluorescence spectrophotometer at different irradiation times. Tumor cells were co-incubated with the nanoparticles and irradiated with a 660 nm laser. ROS levels within the tumor cells were detected using immunofluorescence, and the ratio of dead to live tumor cells was determined using PI/Calcein-AM staining.

Results Prepared DBN/TFN@PEG nanoparticles with hydrated particle size of approximately 107.8 nm were uniformly distributed in the solution. Compared to conventional nanoparticles, the ROS production capacity of DBN/TFN@PEG was significantly higher (P＜0.01). Immunofluorescence results showed that the generation of ROS levels in the tumor cells of DBN/TFN@PEG group were significantly higher than in the conventional nanoparticles group under laser irradiation (P＜0.01). PI/Calcein-AM staining results indicated a significantly higher ratio of dead tumor cells in the DBN/TFN@PEG group compared to the conventional nanoparticle group (P＜0.01).

Conclusions DBN/TFN@PEG has stable physicochemical properties and uniform distribution in the solution. As effective photosensitizers, DBN/TFN@PEG can exhibit stronger ability to induce ROS generation in tumor cells, and may enhance the efficacy of photodynamic therapy in cancer.