A Novel Large-Diameter Optical Fiber Glucose Biosensor Based on Glucose Oxidase– Graphene Oxide–Gold Nanoparticles

A novel glucose large-diameter optical fiber localized surface plasmon resonance (LSPR) sensor was constructed based on chemical cross-linking and electrostatic methods of glucose oxidase–graphene oxide–gold nanoparticles (GOD–GO–AuNPs). The GOD-catalyzed oxidation of glucose reacts with oxygen to produce gluconic acid and $\text{H}_{{2}}\text{O}_{{2}}$ , leading to a change in its ambient refractive index, which in turn leads to a significant shift in the LSPR peak of GO–AuNPs on the fiber. The structure and morphology of GOD–GO–AuNPs were studied by Fourier transform infrared spectroscopy (FTIR), UV–Vis spectroscopy, SEM, and transmission electron microscopy (TEM), respectively. GO improves the stability of the composite particles, reduces the biotoxicity of the metal particles, and the immobilization of glucose oxidase (GOD) on the surface of the composite particles improved the enzyme activity. A fiber-optic sensor was prepared based on the optimal conditions, and the sensitivity of the sensor was 11.134 nm/(mg/mL) in the range of 0–1 mL with a response time of 55 s. It showed good anti-interference and selectivity and can be used for real detection. This method combines the advantages of GO, AuNPs, and large-diameter optical fibers, which show promise for simple, stable, and cost-effective applications in the field of glucose detection.