Advanced search
Start date

Efect of antimicrobial on chemical strucuture and metabolism of storage polysaccharides from cariogenic biofilm

Grant number: 16/24042-2
Support type:Scholarships in Brazil - Doctorate
Effective date (Start): May 01, 2017
Effective date (End): March 31, 2020
Field of knowledge:Health Sciences - Pharmacy
Cooperation agreement: Coordination of Improvement of Higher Education Personnel (CAPES)
Principal Investigator:Carolina Patrícia Aires Garbellini
Grantee:Ana Carolina dos Santos Ré
Home Institution: Faculdade de Ciências Farmacêuticas de Ribeirão Preto (FCFRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil


Considering that bacterial storage polysaccharides may be an important factor for dental caries development and that its characterization could contribute to the understanding of a cariogenic biofilm formation, the aim of the present study is to evaluate in vitro the effect of chlorhexidine (CHX) on the chemical structure of soluble extracellular (SEP) and intracellular polysaccharides (IPS) extracted from the pathogenic biofilm matrix, also evaluating the bacterial metabolism of these polymers. The project will be developed in two stages, the first one being the determination of a method of extraction and purification of IPSs. Thus, S. mutans UA 159 biofilms will be formed and IPSs will be extracted and purified based on two factors: temperature and sonication. The resulting IPSs will be evaluated in relation to their monosaccharide composition. The best method will be selected for the next study. The second stage of the project will involve the effect of CHX on the production and chemical structure of the storage polysaccharides. Thus, S. mutans UA 159 biofilms will be formed for up to 5 days with "feast-famine" episodes to simulate physiological condition of intermittent exposure to carbohydrates during biofilm formation. Biofilsm will be exposed to 10% sucrose (w/v), 3 min, 8x/day. During the experiment, biofilms Will be treated for 1 min, 2x/day with 0.9% NaCl or 0.12% CHX 0,12%. After the experimental period, the biofilms will be collected immediately and at 1 h, 2 h, 4 h, 8 h, 12 and 24 h after the last exposure to sucrose (n = 3). After biofilm collection, the SEPs and IPSs will be extracted, quantified and characterized structurally by gas chromatographic analysis associated with mass spectrometry. To compare groups, the normality of the residues and the homogeneity of the variances will be analyzed. If distribution of values is normal, ANOVA will be used followed by Tukey post-hoc test for comparison between groups. If the data does not follow a normal distribution, the Kruskal-Wallis test will be used instead. The level of significance of 5% will be accepted. Based on the results of the chemical and metabolic structure of these polymers, therapeutic strategies could be designed to modify the matrix of the dental biofilm and, consequently, to control the disease. (AU)