A simple and highly sensitive flexible sensor with extended-gate field-effect transistor for epinephrine detection utilizing InZnSnO sensing films

• Published in: Talanta (Oxford) Vol. 275; p. 126178
• Main Authors: Pan, Tung-Ming, Lin, Li-An, Ding, Hong-Yan, Her, Jim-Long, Pang, See-Tong
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.08.2024
• Subjects: affordability; ambient temperature; atomic force microscopy; blood serum; electric potential difference; electrochemistry; Epinephrine; Extended-gate field-effect transistor (EGFET); Flexible sensor; human health; humans; hysteresis; InZnSnO sensitive film; mass spectrometry; oxygen; Polyimide; transistors; X-ray diffraction; X-ray photoelectron spectroscopy; Epinephrine; Flexible sensor; Polyimide; InZnSnO sensitive film; Extended-gate field-effect transistor (EGFET)
• ISSN: 0039-9140; 1873-3573; 1873-3573
• DOI: 10.1016/j.talanta.2024.126178

This study introduces a straightforward method for depositing InZnSnO films onto flexible polyimide substrates at room temperature, enabling their application in electrochemical pH sensing and the detection of epinephrine. A comprehensive analysis of these sensing films, spanning structural, morphological, compositional, and profiling characteristics, was conducted using diverse techniques, including X-ray diffraction, atomic force microscopy, X-ray photoelectron spectroscopy, and secondary ion mass spectroscopy. The investigation into the influence of oxygen flow rates on the performance of InZnSnO sensitive films revealed a significant correlation between their structural properties and sensing capabilities. Notably, exposure to an oxygen flow rate of 30/2 (Ar/O2) the ratio of resulted in the InZnSnO sensitive film demonstrating outstanding pH sensitivity at 59.58 mV/pH within a broad pH range of 2–12, surpassing the performance observed with other oxygen flow rates. Moreover, under this specific condition, the film exhibited excellent stability, with a minimal drift rate of 0.14 mV/h at pH 7 and a low hysteresis voltage of 1.8 mV during a pH cycle of 7 → 4→7 → 10→7. Given the critical role of epinephrine in mammalian central nervous and hormone systems, monitoring its levels is essential for assessing human health. To facilitate the detection of epinephrine, we utilized the carboxyl group of 4-formylphenylboronic acid to enable a reaction with the amino group of the 3-aminopropyltriethoxysilane-coated InZnSnO film. Through optimization, the resulting InZnSnO-based flexible sensor displayed a broad and well-defined linear relationship within the concentration range of 10−7 to 0.1 μM. In practical applications, this sensor proved effective in analyzing epinephrine in human serum, showcasing notable selectivity, stability, and reproducibility. The promising outcomes of this study underscore the potential for future applications, leveraging the advantages of electrochemical sensors, including affordability, rapid response, and user-friendly operation. [Display omitted] •Structural and sensing properties of InZnSnO sensitive films were investigated under various oxygen flow rates.•EGFET sensor with an oxygen flow rate of 30/2 exhibited the best sensing performance.•InZnSnO-based sensor demonstrated a broad and well-defined linear relationship within the concentration range of 10−7 to 0.1 μM.