TR4 Molecular Based On Aggregation-induced Emission Property For Caries Prevention And Therapeutic Evaluation

As a multiple bacterial disease, caries can lead to secondary apical periodontitis, pulpitis or even damage to the crown if it cannot receive timely treatment, which will seriously affect the health and quality of human life. Efficient, accurate early diagnosis and developing appropriate prevention approaches are currently hot issues in dental medicine field. In recent years, because of its size effect, unique features and ease of modification, nanobiomaterials have been widely used in medical research. In this study, we developed an amphiphilic material based on nano-drugs TR4 that was applied in early prevention of dental caries and visual assessment. The nanomedicine has the following characteristics and advantages of the prevention and treatment of dental caries:(1) Significant caries preventive effect;(2) Visualization of prevention and evaluation capacity;(3) Stabilized nanostructures.This study includes the following contents: 1. Synthesis and characterization of TR4 molecule. The peptide moiety of TR4 was prepared by solid-phase peptide synthesis method and palmitic acid(PA) coupled to the polypeptide; then carboxylated tetraphenylethylene(TPE-COOH) was used to cap the side chain amine group of the Lys in the peptide(Fmoc-Lys(PA)-Arg-Arg-Arg-Arg-NH2). The results indicate that molecular mass of TR4 is 1395.73, and when the molecule concentration of TR4 exceeds a certain value, the molecule can self-assemble into nanoparticles, in which the TR4 is aggregated induced TPE fluoresce. 2. Study of TR4 in prevention and treatment of dental caries. Effect of TR4 on the prevention of dental caries was studied based on biofilm and enamel as study models. The results indicate that TR4 can combine biofilm to form nanoparticles. Then ammonia producing bacteria break down the peptide moiety of TR4 to form ammonia, which can be used to maintain the biofilm environment above the value of demineralization(pH 5.5). Meanwhile, TR4 can bind to enamel, inhibiting enamel demineralization. The fluorescence intensity of biofilm changed when incubated with TR4, indicating that dental plaque biofilm bacteria can make use of the peptide moiety of TR4. 3. Evaluation of TR4 in the role of dental caries. Biofilm coverage level and enamel demineralization can be used as the evaluation index of dental caries. According to the fluorescence spectrophotometer, the fluorescence intensity of TR4 amount binding to biofilm was verified has a good linear relationship. It was also found that TR4 can be adsorbed on the enamel surface, and when enamel was demineralized, the fluorescence intensity of demineralized part become weak or even disappeared. Experimental results show that the luminescence properties of TR4 can evaluate the demineralization degree of enamel.