CMOS chip for electrochemical monitoring of the metabolic activity of biological cells

An integrated CMOS chip for performing electrochemical experiments, which can continuously monitor the metabolic activity of biological cells, is presented. The chip comprises an array of 1024 platinum working electrodes, 64 current readout channels, an integrated potentiostat with on-chip counter, as well as reference electrodes and a temperature sensor. Two different sigma-delta analog-to-digital converters are implemented to realize the current measurement. The first-order sigma-delta converter has a linearity and resolution of better than 11 bits, whereas the second-order sigma-delta converter achieves a resolution and linearity of better than 12 bits. The current range can be set from 2 μA down to 100 pA. The chip package comprises small wells for the cells and reservoirs for the culture media; moreover, it protects the electrical connections. Proof-of-concept measurements of glucose concentrations are shown.