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.