Impacto das nanopartículas de prata na formação de biofilmes por Candida sp. e Streptococcus Mutans isolados da cavidade oral

Abstract

The addition of nanomaterials with antimicrobial activity to dental or hard surfaces can reduce theformation of microbial biofilms, combat infectious diseases in this anatomical site and promoteimproved oral health. Silver nanoparticles are promising agents in the development of alternativesfor the treatment and control of infectious diseases, therefore the present study aimed to synthesizeand characterize silver nanoparticles, evaluate the formation of Candida sp. and Streptococcusmutans biofilms in the oral cavity of students at the State University of Goiás, evaluate the activityof silver nanoparticles against Candida sp. biofilms and evaluate the activity of silvernanoparticles against the formation of Streptococcus mutans biofilms on toothbrushes. Silvernanoparticles were synthesized using the methodology of Lee and Oh (2015) in the absence andpresence of ammonium hydroxide, in this order AgNP(1) and AgNP(2), with nearly sphericalmorphologies of 7.37 nm and 11.40 nm, respectively. Six yeasts of the genus Candida wereidentified, being 2 Candida albicans and 4 Candida krusei, and 8 Streptococcus mutans. BothCandida sp. and S. mutans isolates were able to form biofilm in the total biomass assays and inthe quantification of viable microorganisms adhered to the microtubes and toothbrushes. All yeastsevaluated were inhibited by silver nanoparticles. Both AgNP(1) and AgNP(2) inhibited the yeastsCk7; Ck8; Ck11 and Ck12 with the lowest concentrations of 15.11 μg mL-1 for AgNP(1) and15.42 μg mL-1 for AgNP(2). The yeasts most resistant to nanoparticles were Ca2, Ca4 andCaATCC 10231, inhibited with concentrations of 60.46 μg mL-1 of AgNP(1) and 61.71 μg mL-1of AgNP(2). Regarding fungicidal activity, both nanoparticles require concentrations eight times(8x) higher against C. krusei, while for C. albicans the CMF values were identical to the MIC formost yeasts and twice as high for Ca4. Infections caused by biofilm-forming bacteria are difficultto treat, hence the importance of searching for biofilm inhibitors.