Development of an EGFET microsensor with 3D structure for high-specificity cardiac troponin I detection

In this study, we used microelectromechanical systems (MEMS) technology to design a three-dimensional microsensor, which is based on an extended gate field-effect transistor (EGFET), to detect cardiac troponin (cTnI). A planar micro-reference electrode was integrated onto the same chip. All fabrication processes were compatible with integrated circuit and MEMS technologies, and the dimension of our cTnI microsensor was 1.0 cm x 0.8 cm. From measurements, microsensor sensitivity was 11.408 V (ng ml(-1))(-1) and sensing linearity was 0.961 in the 0-0.05 ng ml(-1) range. In the 0.05-1 ng ml(-1) range, sensitivity was 0.887 V (ng ml(-1))(-1) and linearity 0.933. The detection limit was 0.0063 ng ml(-1), and the response time was approximately 300 s. Bridge-type source read-out, temperature correction and temperature compensation circuits were also successfully designed and were used to reduce the influence of temperature on sensing signals.