A Highly Receptive ZnO-Based Enzymatic Electrochemical Sensor for Glucose Sensing

Abstract

The nano-structured Zinc Oxide (ZnO) has been synthesized by using hydrothermal method and modified via doping of Cobalt (Co), Iron (Fe), a mixture of Co and Fe (Co-Fe) for glucose sensing. The formations of pristine ZnO and doped ZnO have been confirmed by X-Ray diffraction (XRD), which suggests the incorporation of doping elements into the ZnO Matrix. The doped samples show a decrement in photoluminescence intensity in comparison to pristine ZnO, which is an indicative of the formation of competitive pathways for the recombination process. (Co-Fe) doped electrode shows better conductivity than other electrodes, which was later modified with Glucose Oxidase (GO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> ) for the application of electrochemical sensor. GOx modified (Co-Fe) doped ZnO sensor exhibits enhanced 2-fold sensitivity ( 32.2 μA mM <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> ) in comparison to the pristine ZnO sensors following the linear range of 0-4 mM, response time 6.21 seconds and K <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>app</i></sup> value of 0.054 mM. This sensor would be a potential candidate in clinical diagnosis, industry, and food science.