||According to the report by the World Health Organization (WHO), cardiovascular disease is the number one killer of global deaths. An estimated 17.7 million people died from CVDs in 2015, representing 31% of all global deaths. When cardiomyocytes are damaged or killed, important components in the cell, such as troponin T and troponin I, are released outside the cell and can be detected in the blood. In order to diagnose early, this thesis aim to develop a rapid extended gate field-effect-transistor (EGFET)-based microsensor for cardiac troponin detection.|
In this research, the EGFET-based cardiac troponin microsensor is developed by micro-electromechanical process technology, which includes three parts: silver/silver chloride quasi-reference electrode, extended gate field effect transistor and potassium chloride gelatin package wafer. The main processing steps of the implemented microsensor in this study involve eight photolithographic and eight thin-film deposition processes. Honeycomb and parallel geometry patterns of the extended gate electrodes with four different size are designed to investigate their impact on the sensitivity. Finally, the combined method immobilizes the cardiac troponin antibody on the extended gate and detects the potential difference of the antibody antigen bond.
The size of the miniature cardiac troponin sensor developed in this paper is 14.1 mm × 7.5 mm × 10 mm. The optimal extended gate is honeycomb geometry pattern with 2.0 mm × 2.0 mm sensing area. Based on the measurement results, the minimum detection limit, sensitivity, sensing linearity and hysteresis voltage are 0.0125 ng/mL, 214 mV/dec, 0.974 and 1.51 V, respectively, as the concentration of the test solution varies from 0 ng/mL to 0.1 ng/mL. The EGFET-based cardiac troponin microsensor developed in this paper has the advatages of small volume, low detection limit, high sensitivity, high linearity and fast response time.