Antibacterial and cytotoxic evaluation of copper and zinc oxide nanoparticles as a potential disinfectant material of connections in implant provisional abutments: An in-vitro study

Objective: This study evaluates the antibacterial activity against mono and multispecies bacterial models and the cytotoxic effects of zinc oxide and copper nanoparticles(ZnO-NPs/Cu-NPs) in cell cultures of human gingival fibroblasts(HGFs). Design: The antibacterial activities of ZnO-NPs and Cu-NPs against 4 bacteria species were tested according to their minimum inhibitory concentrations(MICs) and against mature multispecies anaerobic model by spectral confocal laser scanning microscopy. The viabilities and cytotoxic effects of ZnO-NPs and Cu-NPs to HGFs cell cultures were tested by MTT, LDH assays, production of ROS, and the activation of caspase-3. The results were analyzed using one-way ANOVA followed by Tukey tests, considering p < 0.05 as statistically significant. Results: For all strains, MICs of ZnO-NPs and Cu-NPs were in the range of 78.3 mu g/mL-3906 mu g/mL and 125 mu g/mL-625 mu g/mL, respectively. In a multispecies model, a significant decrease in the total biomass volume(mu 3) was observed in response to exposure to 125 mu g/mL of each NPs for which there was bactericidal activity. Significant differences were found between the volumes of viable and nonviable biomass exposed to nanostructures with Cu-NPs compared to ZnO-NPs. Both NPs induced mitochondrial dose-dependent cytotoxicity, ZnO-NPs increases LDH release and intracellular ROS generation. Cu-NPs at a concentration of 50 mu g/mL induced production of cleaved caspase-3, activating the apoptotic pathway early and at low doses. Conclusions: After 24 h, ZnO-NPs are biocompatible between 78-100 mu g/mL and Cu-NPs below 50 mu g/mL. Antibacterial activity in a monospecies model is strain dependent, and in a multispecies model was a lower doses after 10 min of exposure.

Automated summary

This study evaluated the antibacterial activity and cytotoxic effects of zinc oxide and copper nanoparticles on human gingival fibroblasts. Results showed that both nanoparticles induced dose-dependent cytotoxicity and activation of apoptotic pathways in cells. Additionally, significant differences were found in the antibacterial activities between the two nanoparticles against mono and multispecies bacterial models.