基于锥形微结构保偏光纤的高灵敏无标记免疫传感器的研究

This Project plans to establish and study deeply a new type of highly sensitive label-free immune sensor based on the tapered microstructural polarization maintaining fiber (M-PMF), which effective birefringence may be affected by the microvariation in the refractive index of the surrounding environment. By properly configuring the sensor setup, it may be eliminated as much as possible for the adverse impact of the inherent birefringence of the tapered M-PMF on its response sensitivity to the environmental refractive index microvariation. Therefore, the change information about the effective birefringence of the tapered M-PMF may be fully magnified and then the detection sensitivity greatly enhanced..In this Project, the theoretical model is built to describe the tapered M-PMF. Based on the model, we analyze the relation between the M-PMF structure and taper shape with its optical properties, and investigate the effective birefringence variation of the tapered M-PMF with the surrounding environmental refractive index. The optimization-based analyses instruct the M-PMF fabrication technique and its tapering profile, and design of the sensor configuration in order to establish the highly sensitive fiber refractive index sensor. Based on the above work, the label-free immune sensor may be developed and its sensing sensitivity further increased by improving surface biomimetic modification of the tapered M-PMF and immobilized performance of the immune proteins..This Project aims to track the international frontier of the label-free immune sensing technologies, provide the technical support to biological sensors and promote its applications and developments in related fields such as biomedical science.

本项目拟通过将微结构保偏光纤拉成锥形，利用锥区环境折射率微变化对其有效双折射的影响，构筑一种新型的高灵敏无标记免疫传感器件并展开深入的研究。通过对传感器结构的合理构造，可以尽量消除保偏光纤锥区固有双折射对其在感知环境折射率微变化时响应灵敏度的不利影响，充分放大锥区有效双折射的变化信息，从而突破性提高检测灵敏度。课题拟建立锥形微结构保偏光纤的理论模型，分析微结构保偏光纤结构及锥区形状与其光学特性的关系，探讨锥区有效双折射在其环境折射率影响下的变化。在优化分析的指导下研制锥形微结构保偏光纤，设计传感器结构，构筑高灵敏折射率光纤传感器，在此基础上开展无标记免疫传感器的研究，通过改善锥区表面活性化修饰与免疫蛋白质的固定化性能，进一步提高传感器灵敏度。该项目旨在跟踪国际无标记免疫传感技术的前沿，为生物传感提供新的技术支持，促进其在生物医学等相关领域的应用和发展。

无标记免疫光纤传感器将高灵敏的光纤传感技术与抗原抗体特异性反应相结合，先功能化修饰光纤表面，借助于光纤进行光信号传递的同时感知抗原抗体对光信号状态的影响。本项目通过将保偏光纤的有效双折射作为测量环境折射率的检测参数，创新性的提出通过消除锥形保偏光纤的固有双折射对其在感知环境折射率微变化时响应灵敏度的不利影响，实现灵敏度的线性放大。理论设计并实验研制出三种微结构保偏光纤，通过拉锥实现了响应灵敏度超过103 nm/RIU；从理论上设计了一种微结构D型保偏光纤，其有效双折射对外界折射率变化的响应灵敏度超过105 nm/RIU；通过将熊猫保偏光纤进行拉锥，消除其固有双折射对灵敏度的不利影响，获得了灵敏度从102 nm/RIU量级到105 nm/RIU的线性放大，与此同时还有效抑制了温度的影响，在此基础上开展无标记免疫传感的研究。本项目为高灵敏度折射率光纤传感技术提供了新的方法，为其在相关领域的应用提供技术支持。