Fabrication of Copper Oxide Modified Graphene Composite Sensor for Simultaneous Detection of Biometabolites from Urine

Abstract

It is a common knowledge that the concentration of certain biomarkers in the body accounts for the presence of some diseases. For instance, the unusual levels of uric acid in body fluids may be indicative of gout and hyperuricemia. These biomarkers may be present within the body but may not be detected at very low concentrations and on time to enable proactive treatments, and the consequences may be dire. The current research report features a new approach developed towards fabricating a new copper oxide modified graphene composite sensor with unique nanostructures on a pencil electrode for sensing three biometabolites (xanthine, uric acid and urea) in urine at very low limit of detection (LOD). The surface structures of this composite sensor composed of several electroactive sites for adsorption of desired analytes. This sensor was appropriately characterized by means of Raman spectroscopy, scanning electron microscopy, cyclic voltammetry as well as localized and normal electrochemical impedance spectroscopy. This sensor was significantly sensitive towards uric acid ((LOD = 10 ppm) and urea (LOD = 20 ppm) sensing compared to xanthine (LOD = 50 ppm). Optimization of key sensor parameters towards efficient sensing (e.g. CuO content) were also examined. The efficiency of the composite sensor toward sensing these analytes in the presence of potential interference was investigated using real human urine. Biomolecular sensing of disease biomarkers at low LOD is important in the assessment of health conditions and monitoring treatment progress of patients. Our experimental results demonstrate the efficacy of simultaneously sensing multiple analytes in a complex biological sample. Keywords: Biosensing; Simultaneous detection; Biometabolites; Disease biomarker; Limit of detection