Photoinduced Transport and Activation of Polymer-Embedded Silver on Rice Husk Silica Nanoparticles for a Reusable Antimicrobial Surface

Antimicrobial materials are gaining significant interest as awareness of pathogens spread through contact becomes increasingly prevalent. While various compounds with antibacterial properties have been explored as active ingredients in such materials, many are prone to leaching, leading to undesirable risks to the environment and to human health. Herein, we develop and test a multilayered plastic film filled with silver nanoparticles, long known to be potent antibacterial agents, supported in a silica matrix. Cross-linked methacrylate layers on both sides of these nanostructures prevent leaching even after several uses, making the material essentially benign. Furthermore, we derive silica from rice husk, an abundant and affordable agricultural waste product. Our findings demonstrate that initial irradiation of the material with UVA light facilitates the photothermal migration of nanoparticles towards the material's surface, thereby significantly enhancing its antimicrobial properties. Remarkably, after just 5 min of visible light irradiation, the material exhibits over 99.999% inhibition of bacterial growth. This environmentally friendly plastic composite harnesses visible light to actively combat bacteria, providing an exciting proof-of-concept for future applications in antimicrobial coatings.