Journal of Nanomedicine & Nanotechnology

Abstract

Antibody@Silica Coated Iron Oxide Nanoparticles: Synthesis, Capture of E.coli and Sers Titration of Biomolecules with Antibacterial Silver Colloid

Shiva K. Rastogi, Jamie M. F. Jabal, Huijin Zhang, Charlene M. Gibson, Kevin J. Haler, You Qiang, D. Eric Aston and A. Larry Branen

Silica coated iron oxide (SiO 2 /Fe 3 O 4 + γ- Fe 2 O 3 ) nanoparticles (SIO-NPs; 75±10 nm in diameter) were prepared by encapsulation of iron oxide NPs with silica using sol-gel method and characterized through spectroscopy methods. The SIO NPs were chemically activated by cyanogens bromide and then functionalized with Escherichia coli ( E. coli ) antibodies. These immuno-magnetic (IM NPs) were used to capture and concentrate E. coli from ~ 180 cfu/ mL suspension. The identification of bacteria was performed by plating on nutrient agar, fluorescent microscopy and scanning electron microscopy. Surface enhanced Raman spectroscopy (SERS) was used to identify different biomolecules of bacterial cell upon the interaction of colloidal silver nanoparticle (Ag NPs 6±4 nm) at different period of time. In our previous report we demonstrated the antibacterial property of colloidal Ag NPs. Therefore, current approach, using IM, and Ag NPs and SERS, provide detailed molecular identification of E. coli as Ag NPs interact over the time. This method would be applicable for food safety, environment protection, biological threat material, antibacterial and other routine E. coli identification projects.