Controlled growth of nanocomposite thin layer based on Zn-Doped MgO nanoparticles through Sol-Gel technique for biosensor applications

The sol–gel process was used to manufacture zinc-doped magnesium oxide nano-flakes (Zn-MgO nano-flakes), which were then distributed in chitosan solution to create a nanocomposite thin layer over a glassy carbon electrode (GCE). Chitosan acts as a binder that provides strength and prevents the material on GCE from leaching out. Glucose oxidase (GOx or GOD) an enzyme has been immobilized on the fabricated CH-Zn-MgO nanocomposite thin film by using the physical adsorption method to form a CH-Zn-MgO-GOx nano-sensor. The enzyme GO_x was used to enhance the activity of the nano-sensor by increasing the electron transfer rate. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, and UV–vis spectroscopy were employed to characterize the samples in this study. The morphology of Zn-MgO was flakes-like. EDX analysis showed the presence of Zinc (Zn), Magnesium (Mg), and Oxygen (O). Cyclic voltammetry was performed by depositing Zn-MgO on a glassy carbon electrode. Enzymatic nano-sensors showed a peak current of 1.69 × 10^-5 µA and non-enzymatic nano-sensors showed a peak current of 6.16 × 10^-6 µA at 100 µL/mL glucose concentration. The synthesized nano-sensors were then used for the detection of glucose levels.