Preparation and antibacterial properties of visible-light-active ZnO/Allicin nanocomposites

Although the antibacterial properties of ZnO nanoparticles have been widely studied for potential biomedical applications, their relatively mild antibacterial activity still limits the clinical application of ZnO-based antibacterial materials. Here, we reported a new method to improve the antibacterial activity and visible light absorption of ZnO nanoparticles by incorporating allicin on the surface. The synthesis was performed through a simple condensation reflux reaction to obtain the designed series of ZnO/Allicin composites. FT-IR, XRD, and TEM analysis proved the structure and composition of the obtained composites. All composites show visible light absorption in the UV–visible diffuse reflectance spectroscopy analysis. Through antibacterial activity tests, the ZnO/allincin-1 % sample showed significantly enhanced activity (2-fold increase) against Staphylococcus aureus after visible light excitation. Antibacterial mechanistic investigations reveal that the composition of allicin with the ZnO nanoparticles not only improves ROS productive ability but also enhances the release of Zn²⁺. Overall, this study provides a practical, convenient, and economic strategy to refine the visible light absorption and antibacterial activity of ZnO without introducing more toxic metal ions. In the meantime, this new nanomaterial could be a good starting point for initiating clinically applicable ZnO nanocomposites.