Antimicrobial and Anti-Biofilm Efficacy of Thymol-Loaded Niosomes Against Foodborne Staphylococcus aureus

The rise of antibiotic-resistant pathogens, such as Staphylococcus aureus, demands innovative solutions. Natural compounds like thymol offer potential, but their practical use is often limited by low solubility and stability in water. This research explores enhancing thymol's antimicrobial and anti-biofilm effectiveness through encapsulation in niosomes using a thin-film hydration technique. The optimal formulation (F2), prepared with a 1:2 surfactant (Span 60:Tween 60):cholesterol molar ratio and a 10:1 lipid: thymol molar ratio, achieved a particle size of 298.3 nm, a PDI of 0.242, and high encapsulation efficiency of 72.56%. Characterization via SEM confirmed spherical morphology, while FTIR analysis verified successful thymol entrapment. An in-vitro release study showed a sustained-release profile, with only 22.63% of thymol released after 4 hours. Stability tests demonstrated that the nano-formulation remained more robust when stored at 4°C compared to 25°C. Notably, thymol-loaded niosomes significantly boosted antimicrobial activity against S. aureus, reducing the MIC by up to 8-fold compared to free thymol. The formulation also showed superior bactericidal effects in a time-kill assay and effectively disrupted biofilms. These results indicate that niosomal encapsulation is a promising approach to enhance thymol's stability and effectiveness, positioning it as a valuable natural option for managing foodborne S. aureus.