Atividade antimicrobiana de um nanocompósito de nanocristais baseado em óxido de zinco dopado com nanocristais de prata e óxido de prata

Abstract

Introduction: Although cells and other diseases of the oral cavity have been treated successfully, they are not yet diverse materials, the multifunctional ones are as much the disease for the clinic. Nanocrystals of zinc oxide (ZnO) and silver oxide (AgO) are biocompatible and biocidal materials and their antimicrobial effect in microorganisms such as Ag and AgO-doped ZnO nanocomposites (ZnO: Ag-AgO) have not been studied Objectives: To evaluate the antimicrobial effect of ZnO: Ag-AgO and minimum inhibitory concentration (MIC) for the tested microorganisms, to investigate the behavior and cytotoxicity of the different doped nanocomposites. Material and Methods: Nanocomposites containing three different nanocrystals doped (ZnO: 3Ag, ZnO: 5Ag, ZnO: 7Ag) were tested. The XRD-6000 diffractometer was used to determine the crystalline structure and the mean size, confirming the formation of nanocrystals. The bacterial growth inhibition assay was performed using Escherichia coli (ATCC®25922), Staphylococcus aureus (ATCC®29213) and Streptococcus mutans (ICQS 00504) with the treatment time of 24 and 48 hours for investigation of the minimal inhibitory concentration. The three nanocomposites were tested with different concentrations in 96-well microplates to assess the antimicrobial potential using the MTT assay [3- (4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide]. The evaluation of cellular cytotoxicity was performed with fibroblast cell lines, using the MIC values found by reference, through the MTT cell viability assay. Results: ZnO: 5Ag and ZnO: 7Ag showed higher growth inhibition in the three microorganisms at the lower concentrations, there was no statistically significant difference in treatment times 24 and 48h. In addition, the nanocomposite showed no cytotoxic behavior at MIC concentrations. Conclusion: This is the first demonstration of a new nanocomposite based on the ZnO: Ag-AgO nanocomposite, which could be used as a preventive and therapeutic measure in dentistry. The nanocomposite in the different doping ZnO: 3Ag, ZnO: 5Ag and ZnO: 7Ag presented promising antimicrobial activity and low cytotoxicity.