Baicalin‐Coated Zinc Oxide Nanoparticles: An Efficient Formulation to Combat Staphylococcus aureus Biofilm Formation and Quorum Sensing

Biofilm formation is a major factor in the pathogenicity and antibiotic resistance of Staphylococcus aureus . In this study, we characterized the antibiofilm effects of baicalin‐coated zinc oxide nanoparticles (ZnO‐Baicalin NPs) on the biofilm of S. aureus . ZnO‐Baicalin NPs were characterized by SEM, EDS, UV–vis, DLS, zeta potential, and FT‐IR analyses. The antibacterial activity of baicalin, ZnO, and ZnO‐Baicalin NPs was investigated by well‐diffusion and broth microdilution assays. Biofilm inhibition potential was studied by crystal violet staining, and the effect of different substances on the metabolic activity of a biofilm was investigated by the TTC method. The viability of bacterial cells embedded in biofilm was studied by CFU counting, and qPCR was employed to determine the expression of the quorum sensing (QS) genes ( agrA and agrD ). ZnO‐Baicalin NPs displayed a spherical shape, and the particle size distribution was 35–75 nm. The DLS size was 702 nm, and the zeta potential was 12.3 mV. ZnO‐Baicalin NPs displayed a larger growth inhibition zone (13.3–14.2 mm) than bare ZnO NPs (10.8–12.2 mm). ZnO and ZnO‐Baicalin NPs showed similar inhibitory effects on the planktonic growth of S. aureus , while ZnO‐Baicalin NPs more efficiently reduced biofilm formation (80%–94%) than ZnO NPs (63%–67%). ZnO‐Baicalin NPs reduced the metabolic activity of S. aureus biofilm by 90–95% and considerably decreased the viability of bacteria embedded in the biofilm. The expression level of the agrA and agrD genes in S. aureus treated with ZnO‐Baicalin NPs was reduced to 0.75 and 0.67 folds, respectively. This work presents the antibiofilm potential of ZnO‐Baicalin NPs as an innovative approach to combat S. aureus infections.