Amperometric Immunosensor Based on Magnetic Inorganic Bionanoparticles Sensing Films

Fe3O4 magnetic nanoparticles were prepared using coprecipitation technology by the reaction between FeSO4 and FeCl3. The surface of the magnetic nanoparticles was functionalized with 3-aminopropyltriethoxysilane. The goat anti-human immunoglobulin G (IgG) antibody was covalently linked to amino-modified particles using glutaraldehyde to form magnetic bionanoparticles. The resulting magnetic bionanoparticles were attached onto the surface of solid paraffin carbon paste electrode with the help of a permanent magnet to construct a new amperometric immunosensor. This immunosensor could be used to analyze human IgG. The linear range was in the range of 2.5–400 ng ml−1. The detection limit was 0.75 ng ml−1. The method has offered a simple manipulation platform to construct immunosensor in low cost and easy regeneration. It had been applicable to serum detection in clinical diagnosis.