Excellent Antimicrobial Activity of Fe3O4/SiO2/Ag Nanocomposites.

In this study, a new antimicrobial agent was developed through a synthesis of Fe₃O₄/SiO₂/Ag double nanocomposites using the sol–gel method. The prepared samples were characterized using XRD, SEM, FTIR, UV-Vis, VSM, and antibacterial test. The data analysis results for the Fe₃O₄/ SiO₂/Ag composites showed that Fe₃O₄, SiO₂, and Ag constructed respective spinel cubic, orthorhombic, and amorphous structures in nanometric size. The saturation magnetization of Fe₃O₄/SiO₂/Ag nanocomposites decreased due to the increase in the Ag content. Interestingly, the Fe3O4/SiO2/Ag nanocomposites presented excellent microbial activity. Ag deposition on the Fe₃O₄/SiO₂ surface enhanced the antimicrobial activity of nanocomposites because Ag oxidized to Agþ ion to produce a toxic e®ect in the cells of microorganisms. Furthermore, the Agþ ion created the –S–Ag bond chain and deactivated the microorganism cells. Furthermore, surface plasmon resonance of Ag had an impact on the formation of photo-induced electrons, which produced superoxide radical anions, O₂ − generating a collapsing force that causes the death of microorganisms. [ABSTRACT FROM AUTHOR]