Electronic monitoring of single cell-substrate adhesion events with quasi-planar field-effect transistors

• 16-channel field-effect transistor (FET) devices with planar topography were fabricated.
• Electrical Cell-substrate Impedance Sensing (ECIS) with these FETs is described.
• Cells were cultured on FETs and impedance spectra revealed differences upon adhesion.
• Impedance spectra of single cells were significant when FETs were covered by >75%.
• Our method of ECIS with FETs can expand this technique to single cell assays.

In the present study, we investigate the applicability of open-gate silicon field-effect transistors (FET) with a quasi-planar topography for Electrical Cell-substrate Impedance Sensing (ECIS) of individual cells. These newly developed chips have a thinner gate oxide layer leading to higher transconductance values and therefore to a stronger electrical coupling between the cells and the transistor gates.Three histologically different cell lines were cultivated the FET devices and subjected to microscopic analysis of gate coverage and electrical measurement of cell adhesion. The used measurement technique, called transistor-transfer function (TTF) sensing, is comparable to the well-established ECIS method. The different morphologies of the tested cells resulted in different frequency spectra recorded by the presented method. With our TTF method we are able to extract cell-related parameters such as seal resistance and membrane capacitance from the measured spectra using an equivalent electrical circuit model. The results of our study demonstrate the reliability of the newly developed planar FETs and implicate the applicability of our system to be used as a pharmacological platform for studying the effects of chemical and therapeutic compounds on a variety of cells coming from different histological backgrounds.