Glucose detection using a tilted fiber Bragg grating coated with a GO-PBA composite layer.

Diabetes mellitus is a prevalent chronic disease that requires continuous monitoring of patients' blood glucose levels during therapeutic management. In this study, we propose and experimentally validate a glucose sensor with a low limit of detection (LOD) and a broad measurement range. The sensor consists of a tilted fiber Bragg grating coated with a graphene oxide (GO) layer on the fiber surface, as well as pyrene-1-boric acid immobilized on the GO layer, functioning as bio-recognition elements for specific glucose detection. Experimental results demonstrate that the LOD of the sensor can reach the nanomolar level (10 nM). Moreover, the sensor exhibits a linear response within the range of 10 nM to 10 μM, while maintaining functionality across a broader measurement range of 10 nM to 20 mM. Furthermore, we evaluated the selectivity of the sensor in comparison with fructose and galactose. The results demonstrate that glucose elicits 2-3 times and 3-5 times stronger responses than fructose and galactose, respectively. Finally, we assessed the practical applicability of the sensor by measuring actual serum glucose concentrations at various levels, and the results indicate that it performs comparably to standard glucose solutions. Owing to its compact size, ease of fabrication, and high sensitivity, the proposed sensor holds significant promise for applications in the biomedical and biochemical fields.