Nano-engineered flexible pH sensor for point-of-care urease detection

A. Sardarinejad, D.K. Maurya, K. Alameh, Alfred Chin Yen Tay, Barry Marshall

Research output: Chapter in Book/Conference paperConference paperpeer-review

1 Citation (Scopus)


© 2015 SPIE. Accurate pH monitoring is crucial for many applications, such as, water quality monitoring, blood monitoring, chemical and biological analyses, environmental monitoring and clinical diagnostic. The most common technique for pH measurement is based on the use of conventional glass pH electrodes. Glass electrodes have several limitations, such as mechanical fragility, large size, limited shapes and high cost, making them impractical for implementation as Lab-onchips and pH sensor capsules. Various metal oxides, such as RuO2, IrO2, TiO2, SnO2, Ta2O5 and PdO have recently been proposed for the realization of pH sensing electrodes. Specifically, ruthenium oxide exhibits unique properties including thermal stability, excellent corrosion resistance, low hysteresis high sensitivity, and low resistivity. In this paper, we demonstrate the concept of a miniaturized ion selective electrode (ISE) based pH sensor for point-of-care urease monitoring. The sensor comprises a thin film RuO2 on platinum sensing electrode, deposited using E-beam and R.F. magnetron sputtering, in conjunction with an integrated Ag/AgCl reference electrode. The performance and characterization of the developed pH/urea sensors in terms of sensitivity, resolution, reversibility and hysteresis are investigated. Experimental results show a linear potential-versus-urea-concentration response for urea concentrations in the range 0-180 mg/ml. Experimental results demonstrate super-Nernstian slopes in the range of 64.33 mV/pH-73.83 mV/pH for RF sputtered RuO2 on platinum sensing electrode using a 80%:20% Ar:O2 gas ratio. The RuO2 sensor exhibits stable operation and fast dynamic response, making it attractive for in vivo use, wearable and flexible biomedical sensing applications.
Original languageEnglish
Title of host publicationProceedings of SPIE: Micro+Nano Materials, Devices, and Systems
Place of PublicationUnited States
ISBN (Print)9781628418903
Publication statusPublished - 2015
EventSPIE Micro+Nano Materials, Devices, and Applications 2015 Conference - The University of Sydney, Sydney, Australia
Duration: 6 Dec 20159 Dec 2015


ConferenceSPIE Micro+Nano Materials, Devices, and Applications 2015 Conference
Internet address


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