Ashton, Rhys, Silver, Callum, Bird, Toby et al. (3 more authors) (2023) Enhancing the repeatability and sensitivity of low-cost PCB, pH-sensitive field-effect transistors. Biosensors & bioelectronics. 115150. ISSN 0956-5663
Abstract
Discrete, extended gate pH-sensitive field-effect transistors (dEGFETs) fabricated on printed circuit boards (PCBs) are a low-cost, simple to manufacture analytical technology that can be applied to a wide range of applications. Electrodeposited iridium oxide (IrOx) films have emerged as promising pH-sensitive layers owing to their theoretically high pH sensitivity and facile deposition, but typically exhibit low pH sensitivity or lack repro- ducibility. Moreover, to date, a combined IrOx and dEGFET PCB system has not yet been realised. In this study, we demonstrate a dEGFET pH sensor based on an extended gate manufactured on PCB that is rendered pH sensitive through an electrodeposited IrOx film, which can reliably and repeatably display beyond-Nernstian pH response. Using a combination of complementary surface analysis techniques, we show that the high pH sensitivity and repeatability of the dEGFETs are dependent on both the chemical composition and critically the uniformity of the IrOx film. The IrOx film uniformity can be enhanced through electrochemical polishing of the extended gate electrode prior to electrodeposition, leading to dEGFETs that exhibit a median pH sensitivity of 70.7 ± 5 mV/pH (n = 56) compared to only 31.3 ± 14 mV/pH (n = 31) for IrOx electrodeposited on non- polished PCB electrodes. Finally, we demonstrate the applicability of these devices by demonstrating the detection and quantification of ampicillin due to β-Lactamase enzyme activity, thus laying the foundation for cheap and ubiquitous sensors which can be applied to a range of global challenges across healthcare and environmental monitoring.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2023 The Authors. |
Keywords: | pH sensor,Discrete ISFET,β-Lactamase |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Electronic Engineering (York) The University of York > Faculty of Sciences (York) > Physics (York) |
Funding Information: | Funder Grant number EPSRC EP/J01771X/1 |
Depositing User: | Pure (York) |
Date Deposited: | 22 Feb 2023 10:00 |
Last Modified: | 25 Nov 2024 00:40 |
Published Version: | https://doi.org/10.1016/j.bios.2023.115150 |
Status: | Published |
Refereed: | Yes |
Identification Number: | 10.1016/j.bios.2023.115150 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:196635 |
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Description: Ashton et al. 2023 - Enhancing the repeatability and sensitivity of low-cost PCB, pH-sensitive field-effect transistors
Licence: CC-BY 2.5