A renewable potentiometric immunosensor based on Fe3O4 nanoparticles immobilized anti-IgG

A renewable potentiometric immunosensor for detection of immunoglobulin G (IgG) has been developed by magnetic force attraction of Fe3O4 nanoparticles immobilized goat-anti-human IgG antibody. For preparing sensitive film of the sensor, cysteine was bonded on the nano-Fe3O4 particles surface. The cysteine functionalized magnetic nanoparticles was attracted on a solid paraffin carbon paste electrode surface to covalently immobilize of anti-immunoglobulin G (anti-IgG) by employing a conventional glutaraldehyde-crosslinking method. The immunosensor showed a specific response to human immunoglobulin G in the range of 0.1-1.2 ng/mL with a detection limit of 0.023 ng/mL. The immunosensor based on the magnetic nanoparticles was made easily by this method. It can be used expediently, renewed easily and low-cost relatively. The renewable potentiometric immunosensor with better stability and higher sensitivity can be employed extensively in clinical diagnosis, monitoring of disease and environmental studies and etc.