A Core–Shell Au@TiO(2) and Multi-Walled Carbon Nanotube-Based Sensor for the Electroanalytical Determination of H(2)O(2) in Human Blood Serum and Saliva

A hydrogen peroxide (H(2)O(2)) sensor was developed based on core–shell gold@titanium dioxide nanoparticles and multi-walled carbon nanotubes modified glassy carbon electrode (Au@TiO(2)/MWCNTs/GCE). Core–shell Au@TiO(2) material was prepared and characterized using a scanning electron microscopy and energy dispersive X-ray analysis (SEM/EDX), transmission electron microscopy (TEM), atomic force microscopy (AFM), Raman spectroscopy, X-ray diffraction (XRD) and Zeta-potential analyzer. The proposed sensor (Au@TiO(2)/MWCNTs/GCE) was investigated electrochemically using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The analytical performance of the sensor was evaluated towards H(2)O(2) using differential pulse voltammetry (DPV). The proposed sensor exhibited excellent stability and sensitivity with a linear concentration range from 5 to 200 µM (R(2) = 0.9973) and 200 to 6000 µM (R(2) = 0.9994), and a limit of detection (LOD) of 1.4 µM achieved under physiological pH conditions. The practicality of the proposed sensor was further tested by measuring H(2)O(2) in human serum and saliva samples. The observed response and recovery results demonstrate its potential for real-world H(2)O(2) monitoring. Additionally, the proposed sensor and detection strategy can offer potential prospects in electrochemical sensors development, indicative oxidative stress monitoring, clinical diagnostics, general cancer biomarker measurements, paper bleaching, etc.