Facile fabrication of electrochemical ZnO nanowire glucose biosensor using roll to roll printing technique

A three electrode electrochemical enzymatic biosensor consisting of ZnO nanowires was successfully fabricated using flexographic printing technique. The incorporation of ZnO nanowires at the working electrode provides advantages such as simple functionalization and high surface area for enhanced sensitivity. The flexographic printing technique allows ultra-high throughput and low cost mass production of devices due to the roll-to-roll nature of the technique. Therefore, the techniques developed here are prudent to the development of technologies capable of meeting the vast market demand for biosensing. Carbon electrodes, silver/silver chloride reference electrodes and ZnO seed layer precursors were directly printed onto a flexible plastic substrate through flexographic printing. The printing process was optimised to allow a suitable seed layer to be formed on the porous printed-carbon electrode to allow selective growth of ZnO nanowires using a hydrothermal growth method. The ZnO nanowires were subsequently functionalised with glucose oxidase, which was used in this work to form a glucose sensor as an exemplary use of the device. The fabricated nanowire electrochemical biosensing devices showed a typical sensitivity of 1.2 ± 0.2 μA mM−1 cm−2 with a linear response to the addition of glucose over a concentration range of 0.1 mM to 3.6 mM