Tailored Structure and Antibacterial Properties of Silica-Coated Silver Nanoplates by Pulsed Laser Irradiation

We coated triangular-shaped silver nanoparticles, a type of anisotropic nanoplate (NPL), with silica (i.e., prepared Ag@SiO₂ NPLs). When we irradiated Ag@SiO₂ NPLs with nanosecond-pulsed laser light for 10 s, the triangular shape changed to spherical because of the photothermal effect. A high laser power exposed the silver core, and the particles exhibited strong antimicrobial activity. In contrast, at a moderate laser power, the silica layer crystallized, and the particles' antimicrobial activity decreased. Thus, a combination of Ag@SiO₂ NPLs and an appropriately tuned power of pulsed laser irradiation facilitated a decreased or an increased antimicrobial activity.