Preparation and antibacterial activity of CoFe2O4/SiO2/Ag composite impregnated with streptomycin

In the present contribution, we have described a facile fabrication of silver-deposited silanized cobalt ferrite composite (CoFe2O4/SiO2/Ag) through a three-step procedure. A pre-synthesized CoFe2O4 was first coated with silica using Stober method and then silver nanoparticles were deposited onto the surface of silica shell. After characterization of this three-component composite by various techniques, such as XRD, SEM, EDX, TEM and VSM, it was impregnated with streptomycin antibiotic. The antibacterial activity of CoFe2O4/SiO2/Ag alone and in combination with streptomycin was investigated against some Gram-positive and Gram-negative bacteria employing disc diffusion assay. It was observed that the bactericidal effect of this composite, evaluated through the diameter of inhibition zones, was enhanced in combination with streptomycin. This clearly indicates synergistic effect of streptomycin on CoFe2O4/SiO2@Ag composite. The present study has demonstrated that the newly synthesized CoFe2O4/SiO2/Ag composite, when combined with streptomycin, becomes an excellent antibacterial agent. The as-made composite can be readily isolated from aqueous solution via magnetic decantation avoiding contamination of the environment. (C) 2014 Elsevier B.V. All rights reserved.