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.