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

Abstract

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 200 kHz. 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 µm)

Impedimetric Sensing of DNA with Silicon Nanowire Transistors as Alternative Transducer Principle

“…This makes an exact description of the TTF spectra very complex. In earlier publications, we applied PSPICE modeling to describe the ISFET devices for recoding of cellular adhesion . With minor simplifications, also analytical solutions for the transfer function H ( jω ) can be found .…”

Human T cells monitored by impedance spectrometry using field-effect transistor arrays: A novel tool for single-cell adhesion and migration studies

“…All FET devices used in this study have been optimized, therefore providing better results for impedimetric sensing of cellular adhesion (Susloparova et al, 2014). The present FET devices have the almost flat surfaces by minimizing the height of the edges between the contact lines and the open transistor gate area, which allow the T cells to migrate almost unaffected by topographical obstacles (Fig.…”

“…The step height was measured using atomic force microscopy and was found to be approximately 200 nm. With this new device design, cells are no longer preferably adhered on the edge of the contact lines instead of the transistor gate area (Susloparova et al, 2014). Additionally, the size of a transistor gate of our devices is in comparison to the size of an attached single T cell.…”

“…All FETs were fabricated in the cleanroom at the Zweibrücken campus of the University of Applied Sciences Kaiserslautern, Germany. Compared to the former FET devices, the FET devices used in the present study have an almost flat silicon oxide surface on the whole chip, which promotes improved cell attachments on the transistors and unhindered cell migration across the whole chip (Susloparova et al, 2014). Transistor gates were arranged in an array of 12 on a 7 Â 7 mm 2 silicon chip, with a distance of 200 mm between individual gates.…”

“…ECIS is one of the examples for electronic label-free biosensors detecting the cell migration and invasion via impedance changes (Wegener et al, 2000). However, for such ECIS assays, confluent cell cultures are required due to the size limitation of the detection electrodes to be used with the instrumentation (Susloparova et al, 2014). Therefore it is not useful when the intended study model is in the form of single cell cultures.…”