Electrochemical Sensor Integrated Circuits

Supervisor: M. Ortmanns

The electrochemical detection of target molecules, the analysis of bioimpedances and the realization in microsystems have received an increasing attention lately. Chronoamperometry (CA), cyclic voltammetry (CV) and electrical impedance spectroscopy (EIS) are the most common methods that are used for the analysis of endogenous and exogenous molecules or electrical properties of tissues. Depending on the electrode assembly of the electrochemical cell, a highly accurate current or voltage measurement is performed on the working or counter electrode. The working electrode can be functionalized enzymatically, allowing target-selective, label-free measurements. The huge range of applications leads to large demands on the measuring apparatus, namely with respect to DC/AC current and voltage excitation and measurement, their dynamic range, the impedance range, the measurement speed, the spectral measurement bandwidth and the IC design.

The combination of this sensor principle with CMOS technology offers many possibilities such as scalability, small size and avoiding long cables. However, the prior art lacks solutions with respect to implementations of high channel numbers both for the signal recording and generation for EIS, since the circuits are too large, consume too much power or have insufficient bandwidth. On the other side it was shown impressively that e.g. impedance spectroscopy can be used for measuring the barrier integrity of epithelia, which resulted in a stimulus-dependent, dynamic modulation of tight junctions (TJ), allowing to modulate the barrier function of the epithelium.

This project considers multi-channel implementations of such electrochemical measurement techniques on CMOS integrated circuits for use on lung epithelia in vitro.