Investigation of the Influence of the As-Grown ZnO Nanorods and Applied Potentials on an Electrochemical Sensor for In-Vitro Glucose Monitoring

Abstract

Abstract:The influence of the as-grown zinc oxide nanorods (ZnO NRs) on the fabricated electrochemical sensor for in vitro glucose monitoring were investigated. A direct growth of ZnO NRs was performed on the Si/SiO 2 /Au electrode, using hydrothermal and sol-gel techniques at low temperatures. The structure, consisting of a Si/SiO 2 /Au/GO x /Nafion membrane, was considered as a baseline, and it was tested under several applied potential 0.1-0.8 V. The immobilized working electrode, with GO x and a nafion membrane, was characterized amperometrically using a source meter Keithely 2410, and an electrochemical impedance Gamry potentiostat. The sensor exhibited the following: a high sensitivity of~0.468 mA/cm 2 mM, a low detection limit in the order of 166.6 µM, and a fast and sharp response time of around 2 s. The highest sensitivity and the lowest limit of detection were obtained at 0.4 volt, after the growth of ZnO NRs. The highest net sensitivity was obtained after subtracting the sensitivity of the baseline, and it was in the order of 0.315 mA/cm 2 ·mM. The device was tested with a range of glucose concentrations from 1-10 mM, showing a linear line from 3-8 mM, and the device was saturated after exceeding high concentrations of glucose. Such devices can be used for in vitro glucose monitoring, since glucose changes can be accurately detected.

Vertically grown zinc oxide nanorods functionalized with ferric oxide forinvivoand non-enzymatic glucose detection

“…Well-aligned and high-density ZnO NRs were grown on top of the cleaned FTO substrates using sol-gel and hydrothermal methods and the growth details are adopted from our previously published works [27][28][29]. The hydrothermal growth method is one of the most considered ways to grow metal oxide materials since it is cost-effective, controllable, and reliable.…”