A Low-Voltage and Label-Free Impedance-Based Miniaturized CMOS Biosensor for DNA Detection

This study designs a low-voltage, label-free and fully integrated impedance-based biosensor using standard complementary metal oxide semiconductor (CMOS) technology to compute both capacitance and resistance of the electrode-electrolyte interface. The proposed biosensor circuit is composed of a common-gate transimpedance amplifier (CG-TIA) with two quadrature phase Gilbert cell double-balanced mixers and finally integrated with microelectrode using 0.18 µm Silterra CMOS technology process. The output value of the readout circuit was used to estimate the magnitude and phase of the measured admittance. The developed CG-TIA can achieve a gain of 88.6 dB up to a frequency of 50 MHz. The overall dynamic range was approximately 116 dB.