Fabrication of microfluidic pH sensing chip based on sputtered Sb2O3/Sb thin film working electrode and AgIO3/Ag thin film reference electrode for detection of A549 cells

• Published in: Measurement : journal of the International Measurement Confederation Vol. 233; p. 114781
• Main Authors: Jaiswal, Jyoti, Sasaki, Kazuma, Shinha, Kenta, Kumar Mani, Ganesh, Kimura, Hiroshi, Tsuchiya, Kazuyoshi
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 30-06-2024
• Subjects: A549 cells; Microfluidic chip; pH sensor; Sb2O3/Sb; Sputtering; Thin films; Sb2O3/Sb; Thin films; Microfluidic chip; A549 cells; pH sensor; Sputtering
• ISSN: 0263-2241; 1873-412X
• DOI: 10.1016/j.measurement.2024.114781

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•A microfluidic pH sensing chip was developed using Sb2O3/Sb and AgIO3/Ag thin films.•The PDMS microfluidic channel was prepared using a 3D-printed mold.•The sensing chip was studied using FESEM, XRD, Raman, XPS, and 3D laser microscope.•The chip exhibited good sensitivity of −57.02 ± 1.23 mV/pH, with n = 4 replicates.•In-vitro pH testing with A549 cells validated chip’s real-time pH measurement.
In this study, we present the fabrication and characterization of a microfluidic pH sensing chip designed to detect human lung cancer (A549) cells. The chip utilizes a Sb2O3/Sb thin film as the working electrode and an AgIO3/Ag thin film as the reference electrode, both deposited using the radio frequency (RF) sputtering technique. The PDMS microfluidic channel was prepared using a 3D-printed mold, followed by curing of PDMS within the mold. The fabricated sensing chip demonstrated excellent linear response (R2 ∼ 0.99) and appreciable Nernstian sensitivity (average = -57.02 ± 1.23 mV/pH, n = 4) in a wide pH range of 1.68–10.01. It exhibited good stability over a 48-hour duration with acceptable drift voltage and negligible temperature impact on the sensing performance. Further, in-vitro pH testing of human lung cancer (A549) cells was performed to investigate the real-time pH measurement ability of the developed microfluidic pH sensing chip.