Highly Sensitive Graphene-Assisted Large-Area Kapton-Based Flexible Surface Plasmon Resonance Biosensor for Enzymatic Glucose Detection

The accurate measurement of glucose levels is crucial in various fields, including healthcare, pharmaceuticals, and food quality control. Given its importance in diagnosing and managing diabetes, monitoring pharmaceutical research, and ensuring food safety, there is a pressing need for glucose sensors. In the present work, we demonstrate an ultrathin, large-area, and highly cost-effective Kapton HN-based flexible-SPR (F-SPR) chip for glucose biomolecule sensing. Owing to its beneficial features, the F-SPR sensor chip overcomes the size, shape, and high-cost limitations of conventional SPR sensor chips. Large-area graphene, integrated together with the Kapton HN chips, was used to enhance the performance of the F-SPR chip. The sensors exhibit a maximum sensitivity of 4.0203 nm/mM using a single-layer graphene-based F-SPR chip within a glucose concentration of 0 to 10 mM. In addition, the detection limit of 89.55 μM was achieved with the proposed F-SPR chip in wavelength interrogation, which enables the label-free detection of trace amounts of glucose molecules. The repeatability, stability, and selectivity of the fabricated sensors were validated through systematically controlled experiments. This facile and cost-effective work provides a strategy for developing high-performance F-SPR sensor chips for small biomolecules, such as glucose, with several prospective applications in biomedicine and human health monitoring.