基于白光干涉的纳米级生物膜层厚度测试的研究

Research on Biolayer Thickness Testing of Nanometer Grade Based on White Light Interference

提出了利用光学干涉原理在光纤传感器端面上直接测量生物免疫反应的方法 ,能够测试到纳米级厚度生物膜层的亚纳米级厚度增加量。将生物膜 (如抗原 )固定在光纤探针端面上 ,入射光在光纤—生物层、以及生物层—空气的界面处两次反射 ,由于两束反射光之间存在光程差 ,所以产生干涉现象 ,通过分析干涉谱线可以测量出抗原层的厚度。当抗原和抗体发生免疫反应后 ,生物膜层的厚度产生变化 ,干涉谱线产生移动 ,通过检测干涉谱线的移动来判断样本溶液中是否存在待测抗体。能够测试出亚纳米级生物膜厚度的增加量。给出了测试曲线。该方法测试精度高 ,结果可靠 ,测试系统简单 ,具有较强的实用性 ,并能够进行实时测量。

A method to direct-detect immunoreactions on surface of optical fiber by interference principle is introduced, whose thickness testing precision of bio-layer is up to angstrom grade. A bio-layer(such as antigen) is immobilized on the surface of a optical fiber bio-probe, incident light is reflected twice at two interfaces:optical fiber—bio-layer and bio-layer—atmosphere, because of the existence of optical path difference between the two reflected light beams, interference should form. Thickness of antigen layer can be detected by spectrum analysis. Thickness of bio-layer will change after immunoreactions between antigen and antibody occur, it can be detected by testing the shifting of spectrum, and draw the conclusion whether the specific antibody exists in sample solution. Thickness increase of bio-layer of angstrom level can be detected. Test curves are given. This technique has the advantages of high precision, dependable, quite simple system, good practicability, and could be used in real time detecting.