Synthesis of Magnesium Oxide Nanomaterial and Employing it as an Electrochemical Probe for Hydroxyl Radical

Abstract

A protein-modified carbon paste electrode (CPE) consisting of two separate layers of inorganic magnesium oxide (MgO) nanomaterial and organic poly-o-phenylenediamine (PoPD) was designed for the electrochemical detection of short-lived hydroxyl radical (eOH). The hydroxyl radical is a type of reactive oxygen species (ROS). The generation of hydroxyl radical in the living system was mimicked using the Fenton reaction and was confirmed using UV -Visible spectroscopy. The high reactivity of the hydroxyl radical enables it to impart oxidative damage to the bovine serum albumin (BSA) immobilized on the surface of the fabricated electrochemical sensing platform. The monitoring of the oxidative damage served as an indirect measure of the presence of hydroxyl radicals in the medium. The signals generated from the interaction of the hydroxyl radical with the recognition layer of the proposed electrochemical sensing scaffold were characterized using square wave voltarnmetry (SWV) and electrochemical impedance spectroscopy (ElS). Undoped and Zn2+ doped MgO nanomaterials were synthesized using the fuel combustion method and were used for fabricating carbon paste electrodes. Cyclic voltammetry (CV) was employed to execute the electropolymerization of o-phenylenediamine (o-PD) on the MgO-based CPE to promote facile electron transfer between the anchored protein and the electrode's surface. The degradation of the immobilized protein was investigated in the presence of the solution of hydrogen peroxide, ferrous (Fe2+) salt, and a combination of both to elucidate the efficiency of the proposed sensing platform. Although the proposed electrochemical probing platform demonstrated high selectivity for the hydroxyl radical, it can only be used once owing to the loss of native characteristics of the immobilized protein post hydroxyl free radical attack. The fabricated BSA immobilized PoPD-modified MgO-based CPE (BSA@PoPD/MgOICPE) sensing platform possesses the ability to detect the abnormal overexpression of the hydroxyl radicals in a living system to prevent pathological disorders encountered at later stages of life.