Disposable and Low-Cost Laser Scribed Graphene Metal Phosphate nanohybrid Electrochemical Sensor for Detection of Serotonin and Hydrogen Peroxide

Abstract

The neurotransmitter serotonin plays a vital role in numerous biological and pathological processes. Hence, its specific and sensitive detection in human serum is essential for preliminary identification of the illness. In this study, an iron (Fe)-functionalized copper/zinc phosphate nanocomposite (Fe@Cu3(PO4)2/Zn3(PO4)2) (FCZP) was synthesised via a straightforward and effective hydrothermal method. The crystalline size and structural morphology were analysed by FT-IR, XRD, BET, HRSEM with EDS, and HRTEM, which revealed a crystalline size of 25.92 nm and a rod-like shape. The sensor demonstrated superior electrochemical sensing performance for both serotonin and H2O2 compared with the other electrodes examined. The sensor exhibited a linear range of 0.1–500 μM, with a limit of detection (LOD) of 0.0391 μM and a good sensitivity of 20.027 μA mM−1 cm2. In H2O2 sensing, FCZP/LIG exhibited a sensitivity of 23.8012 μA μM−1 cm−2 in the linear range of 1 ng/mL–1.0 μg/mL with a limit of detection (LOD) of 0.063 μM. In addition, the electrode showed brilliant stability, reproducibility, and repeatability. For instance, the proposed electrode demonstrated good selectivity among many interfering molecules. This enhanced performance is ascribed to its large specific surface area, numerous active sites, unique structure, and synergistic interaction between Fe@Cu3(PO4)2 and Zn3(PO4)2, all of which collectively enhance the electrochemical activity. Real samples, serum, milk, HeLa cell line, and urine, were examined using the standard addition method, and the recovery rate was significant. The developed electrode material has a considerable potential for analyte detection. Moreover, the antibacterial activity against E. coli and S. aureus reached 85 % inhibition after 72 h of incubation.