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A Potentiometric Indirect Uric Acid Sensor Based on ZnO Nanoflakes and Immobilized Uricase
Department of Science and Technology, Linköping University, Campus Norrköping, Norrkoping SE-60174, Sweden
Department of Electronic Engineering, NED University of Engineering and Technology, Karachi 75270, Pakistan
Nano Biochip Research Group, Institute of Nano Electronic Engineering (INEE), University Malaysia Perlis, Kangar, Perlis 01000, Malaysia
* Author to whom correspondence should be addressed.
Received: 25 December 2011; in revised form: 9 February 2012 / Accepted: 1 March 2012 / Published: 1 March 2012
Abstract: In the present work zinc oxide nanoflakes (ZnO-NF) structures with a wall thickness around 50 to 100 nm were synthesized on a gold coated glass substrate using a low temperature hydrothermal method. The enzyme uricase was electrostatically immobilized in conjunction with Nafion membrane on the surface of well oriented ZnO-NFs, resulting in a sensitive, selective, stable and reproducible uric acid sensor. The electrochemical response of the ZnO-NF-based sensor vs. a Ag/AgCl reference electrode was found to be linear over a relatively wide logarithmic concentration range (500 nM to 1.5 mM). In addition, the ZnO-NF structures demonstrate vast surface area that allow high enzyme loading which results provided a higher sensitivity. The proposed ZnO-NF array-based sensor exhibited a high sensitivity of ~66 mV/ decade in test electrolyte solutions of uric acid, with fast response time. The sensor response was unaffected by normal concentrations of common interferents such as ascorbic acid, glucose, and urea.
Keywords: ZnO nanoflakes (ZnO-NFs); potentiometric nanosensor; uricase; Nafion® membrane
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Ali, S.M.U.; Ibupoto, Z.H.; Kashif, M.; Hashim, U.; Willander, M. A Potentiometric Indirect Uric Acid Sensor Based on ZnO Nanoflakes and Immobilized Uricase. Sensors 2012, 12, 2787-2797.
Ali SMU, Ibupoto ZH, Kashif M, Hashim U, Willander M. A Potentiometric Indirect Uric Acid Sensor Based on ZnO Nanoflakes and Immobilized Uricase. Sensors. 2012; 12(3):2787-2797.
Ali, Syed M. Usman; Ibupoto, Zafar Hussain; Kashif, Muhammad; Hashim, Uda; Willander, Magnus. 2012. "A Potentiometric Indirect Uric Acid Sensor Based on ZnO Nanoflakes and Immobilized Uricase." Sensors 12, no. 3: 2787-2797.