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.

中文翻译：

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使用氧化石墨烯功能化的双折射长周期光纤光栅进行光学葡萄糖检测

我们提出了一种基于酶促氧化石墨烯 (GO) 功能化 π 相移长周期光纤光栅 (PS-LPFG) 的光学葡萄糖传感器，该光栅通过 CO2 激光照射刻在高双折射光纤 (HBF) 上。为了制造灵敏且选择性的传感器头，我们将 GO 和共价固定的葡萄糖氧化酶 (GOD) 涂覆在 HBF 上的 PS-LPFG（称为 HB-PS-LPFG）上。当酶促GO功能化的HB-PS-LPFG（即传感器头）浸入葡萄糖溶液样品中时，固定化的GOD催化葡萄糖氧化为葡萄糖酸，导致局部传感区域的折射率（RI）发生变化的纤维。这些 RI 变化会导致 HB-PS-LPFG 的透射光谱发生变化，并且可以通过测量光谱位移来量化样品的葡萄糖浓度。由于 HBF 的双折射，制造的 HB-PS-LPFG 具有与偏振相关的衰减下降，其在葡萄糖浓度和温度变化（分别为 ΔC 和 ΔT）下表现出透射水平或波长的变化。从这些衰减下降中，我们选择了两个下降（指定为 AD 1 和 AD 3）作为传感器指标，因为它们对 5 至 25 mM 葡萄糖浓度范围内的 ΔC 和 25°C 温度范围内的 ΔT 表现出线性且独立的响应分别为 45°C。两种指标的葡萄糖浓度和温度诱导的敏感性计算为 AD 1 的~0.0 pm / mM 和~86.8 pm / °C 和 AD 3 的~20.8 pm / mM 和~149.2 pm / °C，分别，这揭示了同时测量的传感器能​​力。凭借传感器头的这些独特的 ΔC 和 ΔT 响应，我们的传感器可以以具有成本效益的方式检测葡萄糖浓度，最大限度地减少温度引起的测量不确定性。