Dual-mode glucose sensor based on TFBG-SPR and electrospun PAN/CQDs nanofibers for fluorescence prescreening and precise quantification

As the global prevalence of diabetes continues to rise, the need for accurate and reliable glucose monitoring has become ever more critical. A highly sensitive glucose sensor was fabricated by integrating surface plasmon resonance (SPR) and fluorescence mechanisms onto a tilted fiber Bragg grating (TFBG). A 50 nm thick gold film was deposited on the surface of TFBG and functionalized with 11-mercaptoundecanoic acid (MUA), and then gold nanoparticles-glucose oxidase (AuNPs-GOD) were immobilized on the gold film by l-ethyl-3(3-dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) coupling reaction. In addition, Polyacrylonitrile (PAN) nanofiber membrane doped with carbon quantum dots (CQDs) was electrospun onto the sensor surface to utilize hydrogen peroxide (H₂O₂)-induced fluorescence quenching as a pre-screening indicator for glucose. Experimental results show that the sensor achieves dual-mode detection through spectral changes and fluorescence attenuation, with sensitivities as high as 0.0116 dB/(mg/dL) and 0.0107 dB/(mg/dL) in standard solutions and real urine samples. This dual-mode sensor offers great potential for urine glucose monitoring and biomedical sensing applications.