Preparation, Characterization and Antimicrobial Activity of Core-satellite Ag/PDA@SiO2@CoFe2O4 Magnetic Composites

Abstract

Monodisperse submicron CoFe2O4 spheres were prepared by solvothermal method. Polydopamine-coated silica@CoFe2O4 composite particles were synthesized by combination of Sol-Gel process and in situ self-polymerization method, in which tetraethyl orthosilicate (TEOS) and dopamine were used as the precursor for silica and polydopamine (PDA), respectively. The PDA@SiO2@CoFe2O4 composites had a multilayer core-shell structure with PDA as the outermost layer shell. Then, numerous of silver nanoparticles were assembled on the surface of PDA@SiO2@CoFe2O4 via the reduction of Ag+ by the surface PDA on the composites. The morphology, structure, and composition of the composites were characterized by transmission electron microscope (TEM), X-ray powder diffraction (XRD), X-ray photoelectron spectrometry (XPS), vibrating sample magnetometry (VSM), and inductively coupled plasma optical emission spectrometry (ICP-OES). Antibacterial experiments indicated that the as-prepared composites could restrict up to 92% Escherichia Coli (E.Coli) and Staphylococcus Aureus (S.Aureas) at 0.6 mg/mL Ag. In addition, the composites showed a strong magnetic response to an externally applied magnetic field, so it could be reused.