Example：10.1021/acsami.1c06204 or Chem. Rev., 2007, 107, 2411-2502
Optical glucose detection using birefringent long-period fiber grating functionalized with graphene oxide Optical Engineering (IF1.084), Pub Date : 2021-08-01, DOI: 10.1117/1.oe.60.8.087102 Seul-Lee Lee, Jihoon Kim, Sungwook Choi, Jinsil Han, Yong Wook Lee
We propose an optical glucose sensor based on an enzymatic graphene oxide (GO)-functionalized π-phase-shifted long-period fiber grating (PS-LPFG) inscribed on high-birefringence fiber (HBF) by CO2 laser irradiation. To fabricate a sensitive and selective sensor head, we coated the PS-LPFG inscribed on HBF (referred to as the HB-PS-LPFG) with GO and covalently immobilized glucose oxidase (GOD) on the coated GO film. When the enzymatic GO-functionalized HB-PS-LPFG (i.e., the sensor head) is immersed in glucose solution samples, the immobilized GOD catalyzes the oxidation of glucose to gluconic acid, resulting in refractive index (RI) changes in the local sensing region of the fiber. These RI changes lead to variations in the transmission spectrum of the HB-PS-LPFG, and the glucose concentration of the sample can be quantified by measuring spectral shifts. Owing to the birefringence of HBF, the fabricated HB-PS-LPFG had polarization-dependent attenuation dips, which exhibited variations in transmission level or wavelength for both glucose concentration and temperature changes (ΔC and ΔT, respectively). From these attenuation dips, we selected two dips (designated as AD 1 and AD 3) as sensor indicators because they showed linear and independent responses to ΔC in a glucose concentration range of 5 to 25 mM and ΔT in a temperature range of 25°C to 45°C, respectively. The glucose concentration and temperature-induced sensitivities of the two indicators were calculated as ∼0.0 pm / mM and ∼86.8 pm / ° C for AD 1 and ∼20.8 pm / mM and ∼149.2 pm / ° C for AD 3, respectively, which revealed the sensor capability of simultaneous measurement. With these unique ΔC and ΔT responses of the sensor head, our sensor can detect glucose concentration in a cost-effective way, minimizing the temperature-induced measurement uncertainty.