A tapered single-mode coreless single-mode (SCS) structure with high sensitivity for sensing refractive index is described. In order to achieve high specificity of optical biosensors, here enzyme capsulation film was achieved by embedding urease in zeolitic imidazolate framework (ZIF-8/urease) through in situ growth approach on the coreless fibers. Determination of urea is achieved through online monitoring of its binding to the urease in zeolitic imidazolate framework. Refractive index change result in wavelength shifts of the optical fiber biosensor. The resonance wavelength exhibits a good linear relationship with urea concentration in the range of 1 to 10 mM with detection limit of 0.1 mM and sensitivity of 0.8 mM/RIU (refractive index unit) if operated with broadband light ranging from 1525 nm to 1590 nm. Final assessment of optical biosensor in real sample was performed where excellent performance in terms of sensitivity and selectivity was observed. Schematic representation of experimental setup and mechanism for urea detection. A tapered single-mode coreless single-mode (SCS) structure is placed between a broadband light source ranging (BBS) and optical spectrum analyzer (OSA). ZIF-8/urease composites are applied as a recognition layer for urea detection. Schematic representation of experimental setup and mechanism for urea detection. A tapered single-mode coreless single-mode (SCS) structure is placed between a broadband light source ranging (BBS) and optical spectrum analyzer (OSA). ZIF-8/urease composites are applied as a recognition layer for urea detection.

中文翻译：

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用于锥形光纤尿素生物传感器的具有固定化脲酶的金属有机沸石骨架

描述了一种具有高灵敏度感测折射率的锥形单模无芯单模 (SCS) 结构。为了实现光学生物传感器的高特异性，这里通过在无芯纤维上的原位生长方法将脲酶嵌入沸石咪唑酯骨架（ZIF-8/脲酶）中来实现酶包膜。尿素的测定是通过在线监测其与沸石咪唑酯骨架中脲酶的结合来实现的。折射率变化导致光纤生物传感器的波长偏移。如果在 1525 nm 至 1590 nm 范围内的宽带光下操作，共振波长与尿素浓度在 1 至 10 mM 范围内表现出良好的线性关系，检测限为 0.1 mM，灵敏度为 0.8 mM/RIU（折射率单位）。对实际样品中的光学生物传感器进行了最终评估，在灵敏度和选择性方面观察到了优异的性能。尿素检测实验装置和机制的示意图。锥形单模无芯单模 (SCS) 结构放置在宽带光源测距 (BBS) 和光谱分析仪 (OSA) 之间。ZIF-8/尿素酶复合材料用作尿素检测的识别层。尿素检测实验装置和机制的示意图。锥形单模无芯单模 (SCS) 结构放置在宽带光源测距 (BBS) 和光谱分析仪 (OSA) 之间。ZIF-8/尿素酶复合材料用作尿素检测的识别层。