Green Synthesis of Silver-Decorated Magnetic Particles for Efficient and Reusable Antimicrobial Activity

Metal and metal hybrid nanostructures have shown tremendous application in the biomedical and catalytic fields because of their plasmonic and catalytic properties. Here, a green and clean method was employed for the synthesis of silver nanoparticle (Ag NP)-SiO(2)-Fe(2)O(3) hybrid microstructures, and biomolecules from green tea extracts were used for constructing the hybrid structures. The SiO(2)-Fe(2)O(3) structures were synthesized using an ethanolic green tea leaf extract to form Bio-SiO(2)-Fe(2)O(3) (BSiO(2)-Fe(2)O(3)) structures. Biochemical studies demonstrated the presence of green tea biomolecules in the BSiO(2) layer. Reduction of the silver ions was performed by a BSiO(2) layer to form Ag NPs of 5–10 nm in diameter in and on the BSiO(2)-Fe(2)O(3) microstructure. The reduction process was observed within 600 s, which is faster than that reported elsewhere. The antimicrobial activity of the Ag-BSiO(2)-Fe(2)O(3) hybrid structure was demonstrated against Staphylococcus aureus and Escherichia coli, and the nanostructures were further visualized using confocal laser scanning microscopy (CLSM). The magnetic properties of the Ag-BSiO(2)-Fe(2)O(3) hybrid structure were used for studying reusable antimicrobial activity. Thus, in this study, we provide a novel green route for the construction of a biomolecule-entrapped SiO(2)-Fe(2)O(3) structure and their use for the ultra-fast formation of Ag NPs to form antimicrobial active multifunctional hybrid structures.