Caracterização de Biofilmes de Staphylococcus aureus sobre vidros contendo óxido de zinco: uma abordagem topográfica e nanomecânica em microscopia de força atômica

Abstract

The biofilms formed by Staphylococcus aureus pose a significant challenge in hospital infections, especially on medical devices, due to their resistance to antimicrobial treatments and the host immune system. In this context, the effectiveness of biomaterials, such as bioactive glasses, in combating these infections has been widely studied. This study investigates the topography and nanomechanical properties of S. aureus biofilms grown for 24 hours on glass surfaces doped with different concentrations of zinc oxide (ZnO) (5, 7.5, and 10% (w/w)), using atomic force microscopy (AFM). The results showed that the presence of ZnO significantly impacts the structure and formation of biofilms. On surfaces with 5% ZnO, the biofilm topography revealed an increase in roughness, indicating a defensive response from the bacteria by producing a more robust extracellular matrix. However, higher ZnO concentrations (7.5 and 10% (w/w)) led to biofilm formation inhibition, with a notable reduction in biofilm height and density, resulting in smoother and less colonized surfaces. The nanomechanical properties of the biofilms showed a decrease in the elastic modulus with increasing ZnO concentration, while adhesion force increased. These findings suggest that ZnO can be effective in inhibiting biofilm formation and enhancing the antimicrobial properties of glass surfaces. However, the study revealed limitations, such as variability in biofilm area at high ZnO concentrations, which may affect the robustness of the results. To further understand biofilm-surface interactions and explore potential new technological applications, future research should investigate other ZnO concentrations and different types of surfaces.