Glucose Oxidase/Nano-ZnO/Thin Film Deposit FTO as an Innovative Clinical Transducer: A Sensitive Glucose Biosensor

In the present research, a new biocompatible electrode is proposed as a rapid and direct glucose biosensing technique that improves on the deficiencies of fast clinical devices in laboratory investigations. Nano-ZnO (nanostructured zinc oxide) was sputtered by reactive direct current magnetron sputtering system on a precovered fluorinated tin oxide (FTO) conductive layer. Spin-coated polyvinyl alcohol (PVA) at optimized instrumental deposition conditions was applied to prepare the effective medium for glucose oxidase enzyme (GOx) covalent immobilization through cyanuric chloride (GOx/nano-ZnO/PVA/FTO). The electrochemical behavior of glucose on the fabricated GOx/nano-ZnO/PVA/FTO biosensor was investigated by I-V techniques. In addition, field emission scanning electron microscopy and electrochemical impedance spectroscopy were applied to assess the morphology of the modified electrode surface. The I-V results indicated good sensitivity for glucose detection (0.041 mA per mM) within 0.2-20 mM and the limit of detection was 2.0 μM. We believe that such biodevices have good potential for tracing a number of biocompounds in biological fluids along with excellent accuracy, selectivity, and precise analysis. The fast response time of the fabricated GOx/nano-ZnO/PVA/FTO biosensor (less than 3 s) could allow most types of real-time analysis.