组成图示
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传感器类型
其他（光纤局域等离子体共振(FO-LPR)生物传感器）
检测对象
未具体指明的生物分子分析物（analyte）；样品基质：缓冲液、蔗糖溶液（折射率1.333–1.403）
检测原理
传感基于光纤倏逝场与金纳米粒子局域等离子体共振（LPR）的耦合。飞秒激光在62.5/125 μm多模光纤上刻出U型或D型沟槽，暴露硅芯表面；PAH连接层使Au NPs自组装于沟槽表面，受体进一步固定于Au NPs。样品中的分析物与受体结合后，改变Au NPs表面局部折射指数，使LPR吸收带发生偏移或强度变化。由于小芯径光纤中多次全反射增强倏逝场吸收，结合事件被放大为透射光功率变化。微流控沟槽诱导混沌对流，提高分析物向识别面的传质与混合，从而加快结合动力学。D型六沟槽在结合量、响应时间和机械强度上较优，最终由LED、光电二极管和锁相放大器读出透射功率。
检测灵敏度
分辨率: 4.1 × 10^-7 RIU（D型）；1.8 × 10^-3 RIU（U型）；线性范围: 1.333–1.403 RIU；R = 0.9998（U型）、R = 0.9983（D型）
效应效果
模拟显示，D型光纤结合分析物浓度随沟槽数增加而提高，D型六沟槽峰值比圆形去包层光纤高0.7%，接近其结合性能；U型因沟槽狭窄、底部流速低，主要靠扩散，结合较慢。在20 μL/min下，D型与U型响应时间分别约122 s和206 s；50 μL/min时D型达平衡的97%，U型仅89%。拉伸实验表明D型可承受约250–260 μm伸长，U型约160 μm。折射率传感中，D型分辨率4.1×10^-7 RIU，U型1.8×10^-3 RIU，线性相关系数分别为0.9983和0.9998。作者认为D型六沟槽兼顾结合效率、混合增强与机械强度，适合FO-LPR微流控生物传感。
传感器的构成
- 基底/换能器：62.5/125 μm 多模全硅光纤（Corning 62.5/125 Optical Fiber），芯径62.5 μm、包层125 μm、护套250 μm；飞秒激光部分去除包层与护套形成U型或D型沟槽，暴露硅芯作为波导与传感区
- 表面连接层：聚丙基胺盐酸盐（PAH, poly(allylamine hydrochloride)）3 mM溶液浸渍15 min，以正电荷桥接负电硅表面与金纳米粒子
- 纳米材料修饰层：金纳米粒子（Au NPs）自组装单层，按Natan法制备并浸渍30 min，形成局域等离子体共振（LPR）吸收带，对周围折射率敏感
- 识别元件：受体（receptor，具体类型未指明）功能化于Au NPs表面，用于捕获目标分析物
- 微流控反应通道：500 μm高×500 μm宽×20 mm长微通道，光纤置于中心，样品注入后与受体结合
- 信号读出系统：LED光源（λ=530 nm）、光电二极管（photodiode）、锁相放大器与计算机，测量透射光功率变化
中文摘要
本文报道了一种用于光纤局域等离子体共振（FO-LPR）生物传感器的沟槽光纤设计。传感元件由自组装金纳米粒子修饰的光纤裸纤区构成，金纳米粒子表面进一步功能化受体，通过其局域等离子体共振光学特性实现生物分子识别检测。为提升性能，传感元件与微流控芯片集成，以减少样品和试剂用量、缩短响应与分析时间并提高灵敏度。研究通过数值模拟考察沟槽几何形状对生化结合动力学的影响，将光纤按沟槽形状分为U型和D型。结果表明，D型光纤在生化结合方面表现更优，沟槽可诱导混沌对流以增强微通道混合；D型六沟槽为最优设计。实验证明飞秒激光可加工沟槽光纤，并制备透射式FO-LPR化学传感探针；金纳米粒子修饰的D型光纤折射率分辨率为4.1×10^-7 RIU，显著优于U型光纤的1.8×10^-3 RIU。
英文摘要
Bio-molecular recognition is detected by the unique optical properties of self-assembled gold nanoparticles on the unclad portions of an optical fiber whose surfaces have been modified with a receptor. To enhance the performance of the sensing platform, the sensing element is integrated with a microfluidic chip to reduce sample and reagent volume, to shorten response time and analysis time, as well as to increase sensitivity. The main purpose of the present study is to design grooves on the optical fiber for the FO-LPR microfluidic chip and investigate the effect of the groove geometry on the biochemical binding kinetics through simulations. The optical fiber is designed and termed as U-type or D-type based on the shape of the grooves. The numerical results indicate that the design of the D-type fiber exhibits efficient performance on biochemical binding. The grooves designed on the optical fiber also induce chaotic advection to enhance the mixing in the microchannel. The mixing patterns indicate that D-type grooves enhance the mixing more effectively than U-type grooves. D-type fiber with six grooves is the optimum design according to the numerical results. The experimental results show that the D-type fiber could sustain larger elongation than the U-type fiber. Furthermore, this study successfully demonstrates the feasibility of fabricating the grooved optical fibers by the femtosecond laser, and making a transmission-based FO-LPR probe for chemical sensing. The sensor resolution of the sensor implementing the D-type fiber modified by gold nanoparticles was 4.1 × 10(-7) RIU, which is much more sensitive than that of U-type optical fiber (1.8 × 10(-3) RIU).