Electrochemical Biosensor Based on Interdigitated Electrodes for Determination of Thyroid Stimulating Hormone

Electrochemical biosensor based on interdigitated electrodes was prepared for the sensitive determination of thyroid stimulating hormone (TSH). The interdigitated electrodes used as the sensing structure of biosensor were fabricated by microelectromechanical systems (MEMS) technology. The TSH protein was immobilized to the capture and detection antibodies by enzyme linked immunosorbent assay (ELISA). The enzymatic silver deposition reaction occurred on the glass surface between the interdigitated electrodes. Then the deposition of silver was dispersed on the substrate to make the interdigitated electrodes connected electrically. The TSH concentration could be calculated according to the electrical conductance of interdigitated electrodes. TSH concentrations ranging from 0.02 mIU/L to 100 mIU/L can be readily determined by the electrochemical biosensor based on interdigitated electrodes. A detection limit of 0.012 mIU/L was achieved, which is below the guidelines recommended by the National Academy of Clinical Biochemistry. The proposed electrochemical biosensor can also be used in the detection of other hormones, which are critical for disease early diagnosis