High-throughput impedance spectroscopy biosensor array chip

Abstract

Impedance spectroscopy is a powerful tool for characterizing materials that exhibit a frequency dependent behaviour to an applied electric field. This paper introduces a fully integrated multi-channel impedance extraction circuit that can both generate AC stimulus signals over a broad frequency range and also measure and digitize the real and imaginary components of the impedance response. The circuit was fabricated in a 0.5 μm complementary metal-oxide semiconductor. Tailored for cellular membrane interface characterization, the signal generator produces sinusoidal waves from 10 mHz to 10 kHz. To suit a variety of applications, the impedance extraction circuit provides a programmable current measurement range from 100 pA to 100 nA with a measured resolution of approximately 100 fA. Occupying only 0.045 mm(2) per measurement channel, the circuit is compact enough to include nearly 200 channels in a 3×3 mm(2) die area.