Investigation of ISFET device parameters to optimize for impedimetric sensing of cellular adhesion

In this study we describe how we were able to use an equivalent-electrical circuit for the cell-transistor contact to optimize a future chip design for better performance in cell-substrate adhesion experiments. From our simulations we found that higher capacitances of the source and drain contact lines are able to shift the cell adhesion effects to more moderate frequencies in the range of up to 200kHz. For larger cell-substrate adhesion effects, the transconductance value of the FET devices needs to be increased as well. We used these simulation results to design a new generation of FET devices. These devices were successfully fabricated in our clean room facilities. In electronic cell-substrate adhesion experiments this new generation of devices showed superior performance compared to an earlier version. Most importantly, our new devices have now an almost flat topology enabling future single-cell migration experiments. HEK293 cells adhered with a flat morphology to a newly fabricated FET sensor device (scale bar 50 mu m) (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim