S. YUVASHREE1 and J. BALAVIJAYALAKSHMI2
ABSTRACT
In this study, copper oxide nanoparticles (CuO NPs) decorated reduced graphene oxide (RGO)-chitosan (CS) nanocomposites are prepared for reliable detection of hydrogen peroxide (H2O2). The reduced GO-CS-copper oxide nanocomposites are synthesized by the chemical reduction method. The morphological and chemical structures of the nanocomposites are systemically evaluated by Fourier transform infrared spectral analysis (FT-IR), x-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman analysis. A potential application of reduced GO-CS-copper oxide nanocomposites-modified electrode as a biosensor to monitor H2O2 has been investigated. The electrochemical properties of the biosensor are investigated by cyclic voltammetry (CV). After optimizing all the experimental parameters, the reduced GO-CS-copper oxide nanocomposites on modified glassy carbon electrode (GCE) showed a good performance towards the electrocatalytic reduction of H2O2. This method is simple, cost-effective, sensitive, and also can be used for the determination of H2O2 in a real water sample.
1.1 INTRODUCTION
Graphene, a single layer of sp2 hybridized carbon atoms packed into a dense honeycomb crystal structure, has attracted significant research interest because of its unique structure and extraordinary properties like high conductivity, high surface area, and hardest material [1]. Graphene possesses various material parameters such as superior mechanical stiffness, strength, and elasticity, very high electrical and thermal conductivity that has versatile applications in the areas of the supercapacitor, transistor, solar cells, batteries, fuel cells, hydrogen storage, nanoelectronics, electrocatalysis, sensors, electrochemical devices, electromechanical resonator [2]. Chitosan (CS) is a linear b-1, 4-linked polysaccharide that possesses distinct chemical and biological properties, because of its reactive amino and hydroxyl groups in its linear high molar mass poly glucosamine chains, which are amenable to chemical modification [3]. CS has a lot of excellent characteristics, including film-forming ability, biocompatibility, non-toxicity, good water permeability, high mechanical strength, and adhesion. Graphene and its nanocomposites have been widely exploited in biomedicine for drug/gene delivery, cancer therapy, tissue engineering, and biosensing. In recent years, noble metal nanoparticles have been used widely due to their interesting electronic, optical, mechanical, magnetic, and chemical properties, which differ greatly from those of bulk substances. Among various metal nanoparticles, copper oxide nanoparticles (CuO NPs) have been widely used in many fields due to their excellent physical and chemical properties, easy preparation, and low synthetic cost [4].
Hydrogen peroxide (H2O2), a chemical widely used in pharmaceutical, clinical, environmental, mining, textile, and food manufacturing industries [5], is the by-product of oxidases such as lactate oxidase, urate oxidase, and so on. It is one of the reactive oxygen species (ROS) that plays a vital role in signaling molecules, mainly regulating DNA damage, protein synthesis, cell apoptosis, etc., and it affects cell proliferation and thus leads to cancer, diabetes, and cardiovascular disorders [6, 7]. It is also a relatively stable molecule that makes it highly suitable as a diffusible signaling molecule [8]. Most importantly, the high concentrations of H2O2 initiate neurotoxic events such as Parkinsonās and Alzheimerās disorders. It is critically important to monitor H2O2 levels in biological environments, especially in the cellular environment. However, the electrochemical technique is an optimal choice to actualize the accurate and sensitive determination of H2O2 depending on its inherent advantages, such as low cost, practicality, simplicity, high sensitivity, and fast response [9]. Recently a large range of nanomaterials such as metals, metal oxides, carbon nanotubes (CNTs), graphene, oxide, and nanocomposite materials have been used for the electrochemical detection of H2O2. Additionally, few numbers of polymer-based graphene nanocomposites have been employed for H2O2 sensing [10]. In this present work, CuO NPs decorated on CS functionalized RGO nanocomposites have been synthesized using a chemical reduction method for the electrochemical determination of H2O2. The cyclic voltammetry (CV) is employed to investigate the analytical performance of H2O2.
