基于双折射微纳光纤光栅的免疫传感器机理与实现研究

Fiber evanescent field immunosensor has been exploited for detecting the adsoption reaction between the specific antibody-antigen nearby the fiber surface via evanescent field effect. This immunosensor is a promising technology, owning to that it has not only the features such as real-time monitoring, high sensitivity, but also the capability of unlabeled detecting for trace analysis with the antigen sample unchanged. However, recent related researches simply build up the variation relationship between the wavelength and only one of the factors during immunoreaction, hardly elaborating the complex response mechanism by the evanescent field, which is a competition synthesis of the factors. The undifined sensing mechanism will handicap the development of this type of sensor. This project proposes a novel sensing element, Hi-Bi microfiber Bragg grating, to realize the immune sensing function. By means of the different responses of the sensing wavelengths to the factors which are affected by the immune adsorption, the immunosensing mechanism can be detailed comprehensively. In the project we will investigate the complex mechanism of evanescent field’s response to the immunoreaction and indicate the factor which is the dominated influence of the immunosensitivity. By implementation and optimization method, an improved performance immunosensor will be realized, laying the foundation of fiber sensing technology’s application in real-time and unlabeled immunoassay.

光纤倏逝场免疫传感器不仅具有高灵敏度、可在线监测等特点，还具有非标记探测能力，能够对微量样本进行传感的同时基本保持抗原样本原貌。在免疫反应过程中，复杂的多元因素变化会同时对光纤倏逝场产生影响，然而，目前相关的研究只是简单的针对单一因素的变化进行机制解析，尚未明确对多因素影响的相互作用机制。针对上述问题，本项目提出采用一种新型的传感基元—“双折射微纳光纤光栅”构建免疫传感器，通过其多元检测能力，全面阐释免疫传感中的各因素变化的作用机制，明确影响传感灵敏度的决定性因素。最后通过参数设计与工艺优化等方法实现具高性能的光纤免疫传感器，为此类传感器在非标记免疫检测方面的应用提供完整的科学方案。

免疫传感器的出现地融合了传统的免疫测试法与新兴的生物传感技术，将免疫信息检测推向了定量化和自动化的发展方向，在临床诊疗、食品安全、环境监测以及反恐防爆等领域发挥着重要的作用。. 光纤倏逝场免疫传感器不仅具有高灵敏度、可在线监测等特点，还具有非标记探测能力，能够对微量样本进行传感的同时基本保持抗原样本原貌。然而在免疫反应过程中，复杂的多元因素变化会同时对光纤倏逝场产生影响，其多重作用机制尚未明了。针对上述问题，本项目提出采用双折射微纳光纤光栅构建免疫传感器，通过其多元检测能力，全面阐释免疫传感中的各因素变化的作用机制，明确影响传感灵敏度的决定性因素。最后通过参数设计与工艺优化等方法实现具高性能的光纤免疫传感器，为此类传感器在非标记免疫检测方面的应用提供完整的科学方案，具有良好的应用前景。..项目围绕双折射微纳光纤光栅多元检测机理，在双折射微纳光纤光栅高效制备，免疫感测的实现，增敏设计与实现等几个关键问题展开研究。.1、.理论研究了基于多模通信光纤的椭圆形波导的光学模式特性，优化了微纳光纤的尺寸选择，采用二氧化碳激光器对多模通信光纤进行了截面整形工作，通过对二氧化碳激光功率以及微纳光纤尺寸的优化实现了低损耗、具有高双折射的微纳光纤。.2、.采用193 nm准分子激光器进行光栅制作，实现了双折射光栅的高效写制，基模反射率达到单个偏振3dB，写制时间小于5分钟。基模偏振双峰波长间隔大于2 nm，并具有明显的高阶模耦合反射峰，并对光栅的各个谐振反射峰进行了折射率和温度响应测量。.3、.利用胶联-共价键结合法对将IgG抗原修饰于传感器表面，实现了器件功能化，基模反射峰的检测对IgG抗体的检测极限为10 ug/mL（约为300 nM）。. 最后，以本项目研究为指导，实现了对心肌标志物的特异性检测，检测极限低至10 pg/mL（约为0.1 nM），满足对急性心肌梗塞的早期诊断需求。