Chitosan functionalized Zn/Fe2O3 (Zn/Fe2O3@CS) nanocomposite for ultra-sensitive and selective electrochemical detection of glucose and H2O2.

The development of enzyme-free sensing assays for glucose and H2O2 detection is critical in the field of biological sciences. In this study, a Zn/Fe2O3@chitosan nanocomposite was fabricated using a simple, hydrothermal method and characterized using X-ray diffraction (XRD), fourier-transform infrared (FT-IR), micro-Raman spectroscopy, electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), HR-SEM with EDS, AFM, and HR-TEM. Cyclic voltammetry (CA) and chronoamperometry (CA) were employed to assess the electrochemical behaviour and sensitivity of the newly fabricated electrode toward the detection of glucose and hydrogen peroxide (H2O2). Zn/Fe2O3@FCS nanocomposite exhibited excellent electrochemical sensitivity for the detection of glucose and H2O2. This was attributed to the large surface area of the electrode, which is a preferred property for sensing applications. The glucose sensor exhibited linearity of 1 μM - 5.847 mM, sensitivity of 18.02 μA mM-1 cm-2, limit of detection (LOD) of 0.15 μM, and a rapid response time of 5 s. Similarly, the H2O2 sensor displayed linearity from 1 μM to 6.347 mM, a sensitivity of 22.30 μA mM-1 cm-2, an LOD of 0.11 μM, and a response time of 3 s. The sensor exhibited remarkable selectivity, stability, and reproducibility, demonstrating its practical application in the detection of glucose and H2O2 in serum and live HeLa cells. The fabricated sensor opens up new possibilities for the real-time monitoring of glucose and H2O2 levels in various biological and environmental applications.