An EGFET Based Common Source Amplifier as a Low-Frequency Instrumentation Amplifier for Sensitivity Measurement on RuO₂ Lactic Acid Biosensor

Abstract

In this study, a low-frequency instrumentation amplifier (LFIA) integrated with an extendedgate field-effect transistor (EGFET) is presented to realize the simplicity common source amplifier (CSA) structure. The proposed EGFET CSA was developed by the 0.18-μm CMOS process technology of Taiwan Semiconductor Manufacturing Company (TSMC). The EGFET CSA has low frequency and noise immunity function, and it can effectively output the response signal, with good stability and effectively improve the sensitivity, not susceptible to environmental factors, easy to replace, and low cost. Moreover, the simple circuit design of the EGFET CSA was used to analyze the sensing characteristics and to improve the stability of the ruthenium dioxide (RuO2) lactic acid (LA) biosensor. Therefore, the EGFET CSA is suitable for LA detection. The simple process of the EGFET CSA was used to analyze the sensing characteristics and to improve the stability of the ruthenium dioxide (RuO2) lactic acid (LA) biosensor. An arrayed potentiometric LA biosensor based on the RuO2 thin film was proposed and manufactured in this study. The experimental results indicated that the EGFET CSA as a low-frequency instrumentation amplifier has achieved a good sensitivity (53.41mV/mM) and satisfactory linearity (0.997) on the RuO2 LA biosensor as compared with the V-T measurement system.INDEX TERMS Extended gate field-effect transistor (EGFET), common source amplifier (CSA), ruthenium dioxide (RuO2), lactic acid (LA), low-frequency instrumentation amplifier (LFIA).

High-Performance Potassium-Selective Biosensor Platform Based on Resistive Coupling of a-IGZO Coplanar-Gate Thin-Film Transistor

“…In 1983, Spiegel et al introduced the concept of an extended-gate field-effect transistor (EGFET) to replace the traditional ISFET, with advantages such as a low price, simple structure, easy packaging, long-term stability, light- and temperature-sensitivity, and disposable gate electrodes [ 11 , 12 , 13 , 14 ]. The ion-sensing membrane is separated from the gate of the MOSFET, and only the sensing membrane is immersed in the target solution to detect many target species, such as ions, chemicals, proteins, and viruses, while protecting the MOSFET from chemical damage [ 15 , 16 , 17 , 18 , 19 , 20 ]. However, conventional ISFETs, including EGFETs, despite their many advantages, have a fundamental limitation of sensitivity, referred to as the Nernstian limit, which severely restricts the commercial application of FET-type sensors.…”