Preparation And Biological Application Of Polymeric F Luorescent Nanoparticles Based On Aggregation-Induced Emission

We report a fluorescence self-reporting method based on aggregation-induced emission(AIE)to monitor the formation of polymeric fluorescent nanoparticles(PFPs)sensitively in real time with the copolymerization of vinyl-modified AIEgens TPE-VBC,styrene and maleic anhydride by self-stable precipitation polymerization.It is helpful to understand the mechanism of precipitation polymerization process.We have researched the influences of polymerization temperature,monomer concentration,polymerization time,fluorescent molecule and crosslinking agent on the fluorescence intensity,size and size distribution of the as-prepared polymer nanoparticles after we select the polymerization system.Besides,by making use of the surface reaction,the PFPs with uniform and tunable sizes can be employed for biolabeling and photo-controllable immunotherapy.The main works are as follows:After fluorescence molecules TPE-VBC with AIE properties were synthesized,we precipitation polymerization PFPs by mixing TPEVBC,St,and MAH with a monomer molar ratio of 0.025:0.95:1 in isopentyl acetate(IAAC)and initiating by azobisisobutyronitrile(AIBN)at 60?under nitrogen atmosphere to produce PFPs.It increases gradually from about 95 nm to 309 nm when the reaction time is prolonged from 5 to 90 min.The polydispersity(PDI)of these obtained PFPs is less than 0.15,indicating their narrow size distributions.Therefore,the ideal size PFPs with narrow particle size distribution can be easily prepared.Three developmental stages and the "dynamic hardening" behavior in the growth process were identified by fluorescence self-reporting manner.Two distinct turning points divide the growth process into three stages.In the stage ? of the polymerization,the fluorescence enhances slowly.In the stage ? of polymerization,the fluorescence intensity increases sharply,the emission peak is shifted from 617 to 603 nm dramatically.The results evidently imply the "dynamic hardening" phase changing process during the growth of PFPs.After the stage ?,less TPE-VBC exists in the polymerization solution and their rate of incorporation into the PFPs will be decreased,resulting the fluorescence intensity increased more slowly in the stage ?.Besides,by making use of the surface reaction,the PFPs with uniform and tunable sizes can be employed for biolabeling and photo-controllable immunotherapy.PFPs-coated NK cells demonstrated promoted immunotherapy efficiency to cancer cells.It is found that PFPs could generate reactive oxygen species(ROS)under light irradiation.Such ROS production exerts remarkable photodynamic effect on NK cells when the concentration of PFPs is over 7.5?g/L,while the low concentration of PFPs is not harmful to NK cells both under in dark and light irradiation.PFPs has great potential in biomedical applications because of its good biomarkers and ROS production capacity.