A Biopotentiostat-driven read-out system for transfer characteristic-based graphene FET sensing
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Date
2026-10-19
Authors
Tripathy, Kamalesh
Das, Shrestha
Sica, Marco
Hamidi, Hassan
Iacopino, Daniela
O’Flynn, Brendan
Bhattacharjee, Mitradip
Journal Title
Journal ISSN
Volume Title
Publisher
Institute of Electrical and Electronics Engineers Inc.
Published Version
Abstract
Graphene field-effect transistor (Gr-FET) based sensors have emerged as highly promising platforms for biochemical sensing due to graphene’s exceptional electrical properties and high sensitivity. Most reported Gr-FET biosensors rely on monitoring the drain current at a fixed gate bias voltage to detect biomarkers. However, such single-point measurements are highly dependent on the chosen operating point and are susceptible to device-to-device variations, drift, and ionic screening in electrolyte environments, which often results in ambiguous sensing responses. A more robust approach is to measure the full transfer characteristics and track the shift in the charge neutrality point (CNP), which directly correlates with variations in surface charge distribution caused by biomolecular interactions. However, acquiring transfer characteristics typically requires bulky and expensive laboratory instrumentation, such as precision source-measure units (e.g., Keithley sourcemeters), and parametric analysers, limiting the practicality of such measurements for portable and real-time sensing applications. In this work, a dedicated electronic readout system based on a bio-potentiostat, referred to as the Custom Readout Module, was developed to measure the transfer characteristics of electrolyte-gated Gr-FET sensors to extract the CNP. System performance was validated against measurements obtained with Keithley 2450 source meters, thereby establishing the platform as a portable solution for extracting transfer characteristics for FET-based biosensing. To demonstrate biosensing capability, the graphene channel was functionalised with glucose oxidase, and glucose was detected in phosphate-buffered saline (PBS) via concentration-dependent CNP shifts. The developed platform provides a reliable solution for transfer-characteristic-based graphene FET biosensing, with potential for portable and real-time sensing applications.
Description
Keywords
Graphene , Image sensors , Measurement , Glucose , Field effect transistors , Voltage , Biosensors , Modules (abstract algebra) , Current , Electrodes , Biopotentiostat , Charge neutrality point (CNP) , Custom electronic readout system , Electrolyte-gated graphene FET , Transfer characteristics , [TyndallMicroNano]
Citation
Tripathy, K, Das, S, Sica, M, Hamidi, H, Iacopino, D, O’Flynn, B & Bhattacharjee, M 2026, 'A Biopotentiostat-driven read-out system for transfer characteristic-based graphene FET sensing', IEEE Sensors Journal, pp. 1-8. https://doi.org/10.1109/JSEN.2026.3743185