Preliminary Electrochemical Characterization of Fe3O4/AC-GOx Nanocomposite-Modified Electrodes as Glucose Biosensor Candidates

Abstract

Background: Diabetes is a chronic disease and a major global health problem, characterized by elevated blood glucose levels and potentially leading to serious complications and death. Therefore, accurate and efficient blood glucose monitoring is essential. Objective: This study aimed to develop a glucose biosensor based on a Fe₃O₄/AC-(GOx) nanocomposite using an electrochemical method. Methods: The Fe₃O₄/AC nanocomposite was synthesized using the coprecipitation method, with natural iron sand and coconut-shell-derived carbon as the main precursors. The synthesized nanocomposite was characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and magnetic characterization. The Fe₃O₄/AC-GOx nanocomposite was then applied to a screen-printed carbon electrode (SPCE) for electrochemical evaluation. Results: XRD and FTIR characterization confirmed the formation of the Fe₃O₄/AC nanocomposite and the presence of characteristic Fe–O and carbon-based functional groups. SEM analysis showed an irregular morphology with a tendency to agglomerate and an average particle size of 48.05 nm. The nanocomposite exhibited a saturation magnetization of 9.26 emu/g, with low coercivity and remanent magnetization. The Fe₃O₄/AC-GOx-modified SPCE showed a higher current response than the bare SPCE, indicating improved electrochemical activity. However, glucose-dependent responses and analytical performance parameters have not yet been evaluated. Conclusion: The Fe₃O₄/AC-GOx-modified SPCE shows potential for further development as a glucose biosensor, although systematic analytical validation is still required.