Abstract:

Objective The continuous monitoring of physiological blood glucose levels is a cornerstone in the prevention, management, and diagnosis of diabetes mellitus, driving the demand for advanced glucose sensing technologies. Conventional enzymatic sensors, while effective, face limitations related to enzyme stability and cost. This study focuses on the development of a high-performance non-enzymatic electrochemical sensor, utilizing transition metal copper oxides. The objective is to engineer a sensing platform that leverages the intrinsic electrocatalytic properties of copper oxide nanostructures to achieve superior sensitivity, rapid response, and environmental sustainability, thereby offering a viable alternative to enzyme-based systems.
Method Copper oxide nanofibers were synthesized through a combination of electrospinning and subsequent high-temperature calcination. A precursor solution containing copper nitrate was electrospun to form polymeric nanofiber templates, which were then calcined to yield crystalline CuO nanofibers. These CuO-NFs were subsequently deposited onto a glassy carbon electrode and stabilized with a Nafion binder to construct the GCE/CuO-NFs/Nafion sensor. The morphological and structural characteristics of the synthesized nanofibers were meticulously analyzed using scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The electrochemical performance, including electrocatalytic activity towards glucose oxidation, was evaluated in detail using cyclic voltammetry and amperometric techniques with a standard electrochemical workstation.
Results The characterization results confirmed the successful fabrication of interconnected, one-dimensional CuO nanofibers composed of tightly packed nanoparticles. This unique architecture, characterized by a high aspect ratio, creates a continuous, porous network. This network serves as a specialized conduit for efficient electron transport and exposes a significantly increased density of nanoscale active sites for glucose electrocatalysis. Electrochemical tests demonstrated that the sensor exhibited exceptional catalytic activity for the direct oxidation of glucose in alkaline media. Quantitative performance metrics revealed a high sensitivity of 172.68 μA·L/(mmol·cm²), attesting to its strong signal response per unit concentration change. The sensor also possessed a wide linear detection range from 1 μmol/L to 20 mmol/L, covering both physiological and pathological glucose levels, with a remarkably low detection limit of 0.53 μmol/L. Furthermore, comprehensive assessments confirmed excellent selectivity against common interfering substances (such as ascorbic acid, uric acid, and dopamine), alongside outstanding repeatability, reproducibility, and long-term operational stability over weeks.
Conclusion This research establishes that the structural and catalytic properties of electrospun copper oxide nanofibers can be effectively tuned by modulating precursor concentrations, such as that of Cu(NO₃)₂ in the spinning solution. The constructed GCE/CuO-NFs/Nafion non-enzymatic glucose sensor integrates the advantages of nanofiber morphology—enhanced charge transfer and abundant active sites—to deliver a comprehensive and robust sensing profile. It successfully combines high sensitivity, a broad linear range, and a low detection threshold with reliable anti-interference capability and sustained stability. These collective attributes underscore the sensor's high practical utility and measurement accuracy. Consequently, this work not only provides a viable synthesis strategy for advanced metal oxide nanomaterials but also proves the significant potential and application value of such non-enzymatic architectures in the next generation of affordable, stable, and high-performance glucose monitoring devices for diabetes care.

Key words: electrospinning, CuO material, glucose, electrocatalytic oxidation, nanofiber, sensor, electrode material