Analysis of the susceptibility of peri-implant biofilm to metronidazole after the application of nucleases for the degradation of extracellular DNA present in the matrix

• Grant number: 24/23491-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: March 01, 2025
• End date: February 28, 2026
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: Caroline Dini
• Grantee: Ana Beatriz Torralvo de Freitas
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil

Abstract

The extracellular DNA present in the matrix of peri-implant biofilms has been associated with a probable virulence factor that contributes to resistance to antimicrobial therapies. Therefore, it is necessary to use a strategy that degrades the extracellular DNA present in the matrix and makes it more vulnerable, favoring the effectiveness of antimicrobial action. In this context, this study aims to evaluate the susceptibility of peri-implant biofilm to metronidazole (MTZ) after degradation of the extracellular DNA present in the peri-implant biofilm matrix, using different nucleases, including DNase I and micrococcal, which will be applied to peri-implant subgingival biofilms, using a multi-species in vitro model that mimics the microbial composition of peri-implant infections. For this, four groups will be used: (1) subgingival biofilm 96 h (control); (2) subgingival biofilm 96 h + exposure to DNase I for 2 h + MTZ for 24 h; (3) subgingival biofilm 96 h + exposure to micrococcal for 2 h + MTZ for 24 h; (4) subgingival biofilm 96 h + MTZ for 24 h. The degradation of the extracellular matrix and the effects on the biofilm will be assessed using the crystal violet staining assay to evaluate the biofilm biomass, colony forming units to verify the antimicrobial potential of MTZ associated with the different nucleases, laser confocal microscopy to verify the influence of the treatments on the structure of the biofilms, dry weight, exopolysaccharide dosage and extracellular DNA dosage to evaluate the degradation of the biofilm after the treatments. The quantitative data will be subjected to appropriate statistical analysis with a significance level of 5%.