Diego Vergara-Llanos1, Tania Koning2, Maria Francisca Pavicic3, Helia Bello-Toledo4, Andrés Díaz-Gómez5, Andrés Jaramillo6, Manuel Melendrez-Castro5, Pamela Ehrenfeld7, Gabriela Sánchez-Sanhueza8. 1. Implantology & Rehabilitation Program, Department of Restorative Dentistry, Faculty of Dentistry, Universidad de Concepción, Chile; Dentist Specialist in Implantology, Department of Dentistry, Health Service of Valdivia, Chile. 2. Institute of Inmunology, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile; Centro Interdisciplinario de Estudios del Sistema Nervioso (CISNe), Universidad Austral de Chile, Valdivia, Chile. 3. Institute of Anatomy, Histology and Pathology, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile. 4. Department of Microbiology, Faculty of Biological Science, Universidad de Concepción, Concepción, Chile; Millennium Nucleus for Collaborative Research on Bacterial Resistance (MICROB-R), Santiago, Chile. 5. Advanced Nanocomposites Research Group (GINA), Hybrid Materials Laboratory (HML), Department of Materials Engineering (DIMAT), Faculty of Engineering, Universidad de Concepción, Chile. 6. Department of Mechanical Engineering, Universidad de La Frontera, Temuco, Chile. 7. Centro Interdisciplinario de Estudios del Sistema Nervioso (CISNe), Universidad Austral de Chile, Valdivia, Chile; Institute of Anatomy, Histology and Pathology, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile. Electronic address: ingridehrenfeld@uach.cl. 8. Department of Restorative Dentistry, Faculty of Dentistry, Universidad de Concepción, Chile. Electronic address: gasanchez@udec.cl.
Abstract
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 μg/mL-3906 μg/mL and 125 μg/mL-625 ug/mL, respectively. In a multispecies model, a significant decrease in the total biomass volume(μ3) was observed in response to exposure to 125 μg/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 μg/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 μg/mL and Cu-NPs below 50 μg/mL. Antibacterial activity in a monospecies model is strain dependent, and in a multispecies model was a lower doses after 10 min of exposure.
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 μg/mL-3906 μg/mL and 125 μg/mL-625 ug/mL, respectively. In a multispecies model, a significant decrease in the total biomass volume(μ3) was observed in response to exposure to 125 μg/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 μg/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 μg/mL and Cu-NPs below 50 μg/mL. Antibacterial activity in a monospecies model is strain dependent, and in a multispecies model was a lower doses after 10 min of exposure.