Amperometric immunosensor based on micro electro mechanical systems and gold nanoparticles self-assembled monolayer techniques

A novel immunosensor for the detection of immunoglobulin G has been developed by incorporating the micro electro mechanical systems (MEMS) technology for the preparation of micro amperometric immunosensor and the cysteamine (Cys) based gold nanoparticles (nanogold) self-assembled monolayer (SAM) techniques for the immobilization of IgG antibodis.. Based on MEMS technology, a three-microelectrode system enclosed in a SU-8 reaction microwell was produced. By using self-assembling technique, a Cys monolayer was then formulated on the Au electrode to assemble a nanogold monolayer. Thus, an interfacial design of Au/Cys/nanogold was prepared and used to immobilize IgG antibodies to detect IgG in human serum. The main conditions of the immobilization of IgG antibodies were investigated. Compared with the direct gold attachment procedure and the glutaraldehyde crosslinking procedure, the developed procedure shows improved features including larger amount and higher immunoactivity of the immobilized antibody, lower nonspecific adsorption and broader linear range for the detection of IgG. Moreover, immunosensor based on MEMS technology has attractive advantages, such as miniaturization, compatibility, easier to be designed into microarrays and to realize the simultaneously multi-parameter detection.