Preparation And Intracellular Fluorescence Quantitative Analysis Of AIE Polystyrene Nanoplastics

Nanoplastics have been widely present in the environment as new pollutants,and their ecological hazards have gradually emerged.Due to the small size of nanoplastics and their chemical composition similar to that of living organisms,there is no effective means of separation and detection.This makes it difficult to obtain information on the migration of nanoplastics and their toxic effects on organisms.Conventional organic fluorescence-labeled nanoplastic models are often used to study their biological toxicity.However,conventional organic fluorescence is prone to aggregation-induced quenching(ACQ)phenomenon,which reduces the luminescence performance.In addition,the leakage of conventional organic fluorescence can cause misidentification,resulting in less accurate quantification of nanoplastics.Therefore,in this paper,polystyrene nanoparticles will be labeled with the aggregation-induced emission(AIE)fluorescent agent tetraphenylene(TPE),which does not emit light in dilute solution but emits strong light in the aggregated state and can effectively overcome ACQ while avoiding misidentification caused by free fluorescent molecules.In this thesis,fluorescent polystyrene nanoparticles(TPE@PS NPs)with different sizes and surface functionalization were designed and prepared,and their toxic effects and tracer effects in mouse macrophages were investigated as follows:First,polystyrene nanoparticles(PS NPs)with average sizes of 100 nm,500 nm and 1500 nm were prepared by fine emulsion polymerization,soap-free emulsion polymerization and dispersion polymerization,respectively.Then,TPE@PS NPs with different sizes were prepared by doping TPE into PS NPs through the solubilization method.The effects of tetrahydrofuran(THF)dosage and TPE content on the morphology,particle size and fluorescence properties of TPE@PS NPs were investigated,and the p H stability and light stability of TPE@PS NPs were measured.The effects of functional monomer and TPE content on the particle size and fluorescence intensity of the nanoparticles were investigated,and the surface carboxyl and amino contents of the functionalized TPE@PS NPs were determined by reverse conductivity titration.The carboxyl and amino group contents were determined by reverse conductivity titration.Finally,the tracer effects of TPE@PS NPs of different sizes and different surface functionalization were investigated in mouse macrophages in vitro.The results showed that the toxicity of different sizes of TPE@PS NPs to macrophages was not significant at low concentrations for a short period of time.In contrast,the surface-functionalized TPE@PS NPs all showed a more pronounced cytotoxicity.The fluorescence microscopy results showed that the cells had significant uptake behavior towards the nanoparticles.The mass of nanoparticle uptake by cells was measured by fluorescence spectroscopy standard curve method,and the generalizability of the fluorescence spectroscopy standard curve method was verified quantitatively by flow cytometry.In summary,TPE@PS NPs with different sizes and surface functionalization were designed and prepared in this thesis,all of which exhibited good localization and quantitative tracing effects and are expected to provide model materials for micro-and nanoplastic toxicity studies.