A microchip electrochemical immunosensor fabricated using micromachining techniques

Using micromachining techniques, an electrochemical immunosensor has been designed, fabricated and tested on a Pyrex glass wafer. The sensor has an electrochemical cell that is composed of a reference, an auxiliary and two working electrodes on a spin-coated polyimide film, where the reference electrode is silver and the others are platinum. The polyimide film is used for antibody immobilization instead of a polystyrene sheet which is usually used in conventional immunosensors. A reaction chamber is fabricated separately on a silicon wafer using anisotropic etching techniques. The electrochemical cell on a glass wafer and the reaction chamber on a silicon wafer are then bonded together to construct the immunosensor using polymer bonding techniques. Fabricated immunosensors are tested by the method of cyclic voltammetry (CV) before analyzing the antigen-antibody reaction. Test antibodies are well attached to the polyimide substrate, and the results of the CV test shows that this immunosensor can be successfully applied for electrochemical immunoassay.