MoS2-Graphene heterostructure enhanced fiber optic SPR sensor for highly sensitive glucose detection

Fiber-optic surface plasmon resonance (FO-SPR) sensors, known for the advantages in miniaturization, label-free, and high flexibility, are promising for continuous glucose monitoring. However, due to limited sensing area, FO-SPR sensors exhibit relatively lower sensitivity compared to prism-based SPR sensors. To address this issue, a novel FO-SPR sensor modified with a molybdenum disulfide (MoS 2 )-graphene heterostructure was proposed in this paper. The sensitivity was evaluated both theoretically and experimentally, which showed that the highest sensitivity was achieved with two layers of MoS 2 and two layers of graphene. Moreover, pyrene-1-boronic acid (PBA) was bound to the heterostructure to improve specificity for glucose molecules. It was found that the sensitivity was also further improved by using PBA, and total enhancement of heterostructure and PBA reached 1229.29 % compared to the sensor modified with only a gold film. The newly proposed FO-SPR sensor achieves a sensitivity of up to 12593.06 nm/RIU for glucose concentrations in the range of 0–500 mg/dL, indicating its potential for widespread application in glucose concentration measurement.