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.