A Micro Amperometric Immunosensor Based on Protein A/Gold nanoparticles/Self-assembled Monolayer-Modified Gold Electrode

A novel amperometric immunosensor fabricated by microelectromechanical systems (MEMS) technology with a novel modified procedure for immobilization of antibody on gold electrode has been developed. Based on MEMS technology, immunosensor with a three-microelectrode system integrated with two SU-8 micro pools was fabricated. Employing self-assembled monolayers technique, the working electrode was modified by 1,6-hexanedithiol to assemble gold nanoparticles layer, subsequently, a layer of protein A was immobilized on nanogold layer to further capture antibody. Compared with the amperometric immunosensors using traditionally metal rod/slice electrode or screen-printed electrode, it has attractive advantages, such as miniaturization, compatibility with CMOS techniques and easy to be designed into micro array. Moreover, the studied immunosensor showed high specificity, good reproducibility and broad linear range for the detection of human immunoglobulin (HIgG), which makes it potentially attractive for clinical immunoassays