A 24-Ch. Multi-Electrode Array Allowing Fast EIS to Determine Transepithelial Electrical Resistance

Electrochemical Impedance Spectroscopy (EIS) is a standard method to investigate properties of biological samples due to its non-invasiveness. Multi-electrode arrays (MEA) per-form parallel measurements, which lead to higher throughput and thus reduced measurement time. However, implementing a parallel MEA EIS needs considerations to achieve safe and fast measurements. Commercially available devices perform single EIS and then serially scan the MEA. Their limited frequency range and limited detection impedance can be further increased to support more application. This work presents a 24 channel MEA EIS system that has highly reduced measurement time in comparison to commercially available solutions by utilizing multi-tone excitation signals. The EIS system has been implemented on a two layer PCB and successfully tested with biological samples. It consumes 17.5 × 17.5 cm2 and draws 300 mA from a 5 V supply voltage. The EIS measurement frequency range spans from 10 mHz to 100 kHz and can detect impedances from 6 Ω to 300 kΩ. The prototype measurements have been compared with the commercially available devices and showed matching better than 95%.