MSM Fiber Optic Surface Plasmon Resonance Glucose Sensor Based on SnO2 Nanofibers/Au Structure

Glucose is an indispensable nutrient for metabolism in living organisms and is widely used in food, industry, and medical fields. Glucose is often added as a sweetener in food and often used in industry as a reducing agent for various products. In medical treatment, glucose is added to many drugs as a nutritional additive, and it is also an indicator that diabetics need to pay attention to at all time. Therefore, the market has a great demand for low-cost, high-sensitivity, fast, and convenient glucose sensors, and the industry has always attached great importance to the work of creating new glucose sensor devices. Therefore, we proposed a SnO2 nanofibers/Au structure multimode-single-mode-multimode (MSM) fiber surface plasmon resonance (SPR) glucose sensor. SnO2 nanofibers were fixed to a single-mode fiber core that had been plated with the Au film by electrospinning. When the glucose concentration increased at 5 vol% intervals, the corresponding resonance wavelengths had different degrees of redshifts. Comparing the two structures, as the glucose concentration range increased from 0 vol% to 60 vol%, the sensitivity increased from 228.7 nm/vol% in the Au structure to 337.3 nm/vol% in the SnO2 nanofiber/Au structure. At the same time, the linear correlation between the resonant wavelength and the refractive index of the two structures was greater than 0.98. Moreover, the SnO2 nanofibers/Au structure significantly improved the practical application performance of SPR sensors.