Analytical Chemistry

Facilitating field-effect transistor based (bio)sensor research with a miniaturized bipotentiostat



Field-effect transistors (FETs) have been around for more than half a century and are at the heart of everyday electronics, but field-effect transistor based (bio)sensors are an emerging field with a huge potential that is yet to be explored. These (bio)sensors are useful in the detection of various analytes including ions, small organic molecules, DNA, proteins, and cells. However, the equipment such as parameter analysers or source meters used to characterize FET-based (bio)sensors is typi-cally bulky, expensive and complex, limiting the access to their research and development. There is a need for a compact and portable solution to this problem. It is worth noting that an answer to this conundrum may lie in the knowledge gap between the research communities of electrical/material engineers or physicists working on FETs and the electrochemists focused on potentiometry, which herein we aim to bridge. We present an economical and versatile solution based on an original equipment manufacturer (OEM) product from a leading portable potentiostat developer – PalmSens. Together with their engineers, we repurpose the flexible and affordable EmStat Pico bipotentiostat module to measure a variety of differ-ent commercially available FET sensor architectures – starting from a simple metal-oxide-semiconductor FET (MOSFET) which is then used as a transducer in extended-gate configuration. We then move towards a more complex ion-sensitive FET and a state-of-the-art single-sheet graphene electrolyte gated FET. Using a simple proprietary scripting language, we perform proof-of-concept experiments aimed at popularizing the FET field among electrochemists. We believe that using the EmStat Pico module can help accelerate FET-based (bio)sensor research and bridge the knowledge gap between FET researchers: physicists, electrical/material engineers and chemists. On top of that, the mentioned bipotentiostat is ready to implement in an end-user device, accelerating the commercialization of FET (bio)sensors for e.g. medical diagnostics.


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Supplementary material

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Supplementary information
The supplementary information provides information on: output characteristics of MOSFETs; the potentials (VSD, VG) in time, ap-plied in order to measure different FET characteristics and the con-nection schemes for various FET configurations. Additionally, a exemplary MethodScript is provided.