Effects of green tea derived epigallocatechin gallate on matrix-rich Streptococcus mutans biofilm

Abstract

S. mutans is a bacterial pathogen strongly implicated in dental caries onset and progression. It utilizes dietary sucrose to build up cariogenic biofilms characterized by an acidic milieu and a virulent extracellular matrix. Among potential preventive agents to target the cariogenic biofilm, Epigallocatechin gallate (EGCG) is known to disturb S. mutans viability and growth. However, the therapeutic efficacy of EGCG against S. mutans in a sucrose supplemented environment and matrix-rich biofilm, as found in disease-prone conditions in the oral cavity, has not been adequately investigated. Thus, the aim of this study is to examine the therapeutic effect of EGCG in the presence of a matrix-rich biofilm using a validated S. mutans biofilm model. The effects of EGCG against the matrix-rich S. mutans biofilm will be evaluated through microbiological assays (colony forming unities count, biofilm dry weight, protein quantification), biofilm acid production, biochemical characterization of the biofilm matrix (quantification of polysaccharides), and study of the biovolume (bacterial cells/EPS ratio), 3D biofilm architecture, in situ pH, and synchronized effects of EGCG on the biofilm architecture, in situ pH, and surface demineralization by combining multilabelling approaches of bacterial cells, extracellular matrix, and pH with enamel surface analyses for demineralized areas and mineral content through advanced microscopy techniques. The data obtained will be analyzed with appropriate statistical tests with a significance level set at 5%. Investigating the effects of EGCG in the presence of a matrix-rich biofilm would allow the comprehension of the challenges associated with the development of therapeutic agents to target caries associated biofilms. (AU)