长周期光纤光栅生物膜传感器

Long Period Fiber Grating Biosensor for Detecting Bio-layer Thickness

介绍了一种可测量生物膜层厚度的长周期光纤光栅(LPG)传感器,其原理是在光纤包层(折射率为n2)外涂上特殊的生物活性膜层(折射率为n3),在n3≥n2的条件下,生物膜层厚度的变化将引起LPG谐振波长的改变,通过测量LPG谐振波长的移动量就能得到生物膜层厚度的变化量。该传感器主要用于确定血液里是否存在抗原,用抗体作为生物活性膜层,当测到的谐振波长发生了位移,就可以推知抗体和抗原发生了反应,说明血液中存在抗原。硅化膜的折射率和抗原、抗体物质的折射率非常接近,可作为成膜基底材料,基底膜层厚度可选择在120 nm左右。谐振波长的解调采用可调谐F-P腔干涉解调,结构简单,体积小,易于实用化。

A long period fiber grating（LPG） biosensor for detecting bio-layer thickness is introduced in this paper. The principle of the biosensor is by coating a idiosyncratic bioactive layer.（ with refractive index n3 ） on the fiber cladding （ with refractive index n2 ） , and in the condition of n3 ≥ n2 , the variety of bio-layer thickness brings about variety of resonant wavelengths of LPG. So the variety of bio-layer thickness can be detected by measuring resonant wavelengths of LPG. Main function of the biosensor is to detect antigen in blood while antibody as bioactive layer. Reaction between antigen and antibody occurs and it shows that there is antigen in blood when resonant wavelengths shift is detected. Silicify layer is used as fundus layer since its refractive index is much the same as that of antigen and antibody. The thickness of fundus layer is about 120 nm. Resonant wavelengths is demodulated by using a turnable F-P interferometer of simple and small frame and with practicability.