Silver Inlaid with Gold Nanoparticles: Enhanced Antibacterial Ability Coupled with the Ability to Visualize Antibacterial Efficacy

Silver nanoparticles (Ag NPs) are widely used against bacteria, but further applications are restricted by their cytotoxicity. Their antibacterial efficiency cannot be measured because of the risk of development of multidrug resistance (MDR) with use of antibiotics. An alloy nanostructure of gold nanoparticles (Au NPs) inlaid on Ag NPs was synthesized using egg white protein (denoted here as Au-Ag NPs), exhibiting an enhanced antibacterial effect and can visually indicate the antibacterial efficacy by fluorescence. Interestingly, the fluorescence recovered after antibacterial action. Au-Ag NPs showed enhanced antibacterial effect, due to higher reactive oxygen species (ROS) generation than Ag NPs, after adhering to the surface of bacteria, suggesting that the silver content in Au-Ag NPs can be tuned to reach high antibacterial activity with low cytotoxicity. Au-Ag NPs visualized bacteria by fluorescence changes, which makes the antibacterial process clear and allows the dosage of antibacterial agents to be controlled accurately, which can prevent MDR Efficient antibacterial activity coupled with the ability to visualize bacterial processes allow Au-Ag NPs to be a potential solution in medicine and biosensing.