提出了一种双通道探针式81°倾斜光纤光栅(81°TFG)传感器,并将其用于甲胎蛋白(AFP)的免疫检测研究。首先,在81°TFG端面镀银膜形成反射式81°TFG,构建由2×2耦合器和两支81°TFG探针组成的双通道传感器。然后,在栅区表面修饰大尺寸AuNs粒子和GO,并以AFP单克隆抗体为特异性识别单元修饰栅区表面,实现基于双通道探针式81°TFG局域表面等离子体共振(LSPR)的AFP免疫传感器。最后,在复杂血清环境下完成免疫检测实验,结果表明,该传感器对AFP抗原质量浓度的检测极限在1~10 pg/mL之间,检测的饱和点约为200 ng/mL,灵敏度约为0.155 nm/log(pg/mL),对肝癌患者的血清具有良好的特异性响应。相比单通道透射式81°TFG传感器,该传感器能实现对目标分子阳性和阴性样本的同时对照检测,从而增强临床检测应用中的可靠性,且操作更简便、应用潜力更大。

声表面波(SAW)免疫传感器是一种新型生物传感器, 该文设计并实现了一个高频的SAW免疫传感器检测系统。该系统利用锁相环控制输出信号频率对输入信号频率跟踪锁定, 通过测量频率变化量即能完成对免疫传感器的检测, 通过液晶屏显示结果。测试结果表明, 该检测系统能准确测量频率156~162 MHz内的传感信号, 系统的最大测量误差仅0.85%, 满足SAW免疫传感器高频检测领域的工程实际需要。

降钙素原(Procalcitonin, PCT)对于反映患者炎症甚至败血症患病程度具有重要意义。为实现低浓度PCT的免标记检测, 利用极大倾角光纤光栅(Excessively Tilted Fiber Grating, Ex-TFG)的低温度交叉敏感性和高折射率灵敏度的优点, 在光纤的表面修饰金黄色葡萄球菌(Staphylococcus Aureus Protein A, SPA), 再将PCT单克隆抗体固定在SPA分子层, 从而构成对PCT具有特异性检测功能的免疫传感器。实验结果表明: 降钙素原含量为0.5ng/mL时, 谐振波长红移约13pm; PCT的浓度为200ng/mL时, Ex-TFG的红移量基达约125pm; 浓度为1000ng/mL时, 红移量趋于饱和, 最大红移量约150pm。通过对实验数据拟合, 发现Ex-TFG谐振波长的红移量与PCT浓度之间的关系满足Langmuir模型, 相关性系数为0.98。该方法为低浓度PCT的检测提供了一种免标记、快速的检测方法。

提出一种基于81°倾斜光纤光栅(81°-TFG)的新城疫病毒(NDV)免疫传感器。分析81°-TFG传感器的基本原理和传感特性。利用金黄色葡萄球菌蛋白A(SPA)修饰81°-TFG的表面,然后将自制的高纯度新城疫病毒单克隆抗体(MAbs)通过SPA分子固定于81°-TFG表面,从而制成对NDV抗原特异性检测的传感器。实验结果表明:该免疫传感器对NDV的探测极限在0.1 ~0.2 ng/mL之间,检测饱和点约为1.0 ng/mL;在0~1.0 ng/mL范围内具有良好的线性度(R²约为 0.982),灵敏度约为342 pm/(ng·mL ^-1);且该传感器具有良好的可重用性和对NDV抗原的高度特异性,并能用于NDV的临床检测。相对于传统的免疫荧光技术、酶联免疫等生化检测方法,本文提出的方法具有免标记、操作简便、快速检测等优点。

甲胎蛋白（AFP）是常见的肝癌肿瘤标志物, 在早期诊断方面起到重要作用。 分别设计构建了磁免疫和荧光免疫传感器并将其应用于AFP的定量检测。 在磁免疫传感器中, 采用免疫磁珠代替传统固相载体, 实现了目标物的快速分离; 利用标记抗体上的辣根过氧化物酶（HRP）催化底物显色, 根据底物吸光度值的大小进行定量检测。 构建的AFP检测方法的检出限为36 ng·mL-1, 线性范围为10~80 ng·mL-1。 在荧光免疫传感器中, 将碲化镉量子点（CdTe QDs）的荧光作为信号输出, 并通过同时将多个CdTe QDs连接在纳米硅球表面实现信号放大, 通过测量量子点荧光强度实现定量检测。 该方法AFP检出限为42 ng·mL-1, 线性范围为5~150 ng·mL-1。 所设计的两种传感器均具有特异性强、 灵敏度高的特点, 为AFP的检测提供了新的思路和方法。

Porous silicon (PS) suitable for optical detection of immunoreaction is fabricated. The structure of immunosensor is prepared by the following steps: oxidization, silanization, glutaraldehyde cross-linker, and covalent binding of antibody. When antigen is added into the immunosensor, the Raman intensity is estimated to be linearly reduced according to the concentration of the surface protective antigen protein A (spaA) of below 4.0 μg·ml?1. The ultimate detection limit is 1.412×10^2 pg.ml^{?1}. Controlled experiments are also presented with non-immune antigen of the spaA, and results show that the immunosensor has high specificity. Compared with the conventional enzyme-linked immuno sorbent assay (ELISA), this method is quick, inexpensive, and label-free.

A novel structure with high surface enhanced Raman scattering (SERS) activity and bio-specificity as a SERS-based immuno-sensor (named as Raman reporter-labeled immuno-Au aggregate) is demonstrated and employed for protein detection. In each fabrication process, the features of those aggregates are obtained and characterized by ultraviolet-visible (UV-Vis) extinction spectra, transmission electron microscopy (TEM) images, scanning electron microscopy (SEM) pictures, and SERS spectra. Experimental results indicate that proper amounts of the reporter molecules can result in the moderate aggregation morphologies of gold nanoparticles. Compared with the previously reported method using Raman reporterlabeled immuno-Au nanoparticles, more sensitive SERS-based protein detection is realized with this novel immuno-sensor.