Experimental toothpaste containing Epigallocatechin gallate loaded in chitosan nanoparticles: effects against cariogenic biofilms

• Grant number: 24/01916-3
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: November 01, 2024
• End date: October 31, 2026
• Field of knowledge: Health Sciences - Dentistry - Social and Preventive Dentistry
• Principal Investigator: Silmara Aparecida Milori Corona
• Grantee: Maria Gerusa Brito Aragão
• Host Institution: Faculdade de Odontologia de Ribeirão Preto (FORP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

The objective of this project is to develop an experimental toothpaste containing Epigallocatechin gallate (EGCG) loaded in chitosan nanoparticles and test the effects of this product on the initial growth, maturation, and virulence of Streptococcus mutans biofilm. This project will be developed in three steps: 1) Synthesis and characterization of nanoformulation containing EGCG loaded in chitosan nanoparticles. The nanoparticles produced will be characterized regarding the quantity of EGCG using liquid chromatography, their diameter and Zeta potential by using dynamic light dispersion and microelectrophoresis, and regarding their size by using scanning electron microscopy (SEM). 2) Development of experimental toothpaste: there will be produced a fluoridated base toothpaste, a fluoridated toothpaste containing EGCG loaded in chitosan nanoparticles, and a fluoridated toothpaste containing chitosan nanoparticles. The toothpastes will be characterized by their rheological properties, fluoride content, and cytotoxicity. 3) Analyses of the effects of the experimental toothpastes against cariogenic biofilms. Two experimental regimen will be tested: 1) biofilm initial growth and maturation; 2) virulence of mature biofilms. In experimental regimen 1, enamel slabs will be pre-treated with 0,9% NaCl (negative control), suspension of fluoridated base toothpaste, suspension of fluoridated toothpaste containing EGCG loaded in chitosan nanoparticles, suspension of fluoridated toothpaste containing chitosan nanoparticles, and chlorhexidine 0.12% (positive control) for 1.5 min. 2) In experimental regimen 2, biofilms will be grown on enamel slabs for 19 h without being disturbed. Then, the biofilms will be treated twice a day for 1.5 min with the same treatments described for regimen 1. After 67 h, the biofilms and enamel slabs will be collected for analyses. Effects on biofilm acidogenesis, bacterial viability, polysaccharide synthesis, biofilm dry weight, and control of mineral loss will be evaluated in both regimens tested. For experimental regimen 2, effects on the morphology and 3D structure of the biofilm will be evaluated by advanced microscopy techniques. The data generated will be evaluated by appropriate statistical tests and the development of this study will lead to the production of novel dental hygiene products synthesized with a formulation capable of preventing the formation of cariogenic biofilms and controlling the development of carious lesions.