基于极大倾角光纤光栅的降钙素原免疫传感器

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1 000ng/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。

Study on Procalcitonin Immunosensor Based on Excessively Tilted Fiber Grating

Procalcitonin (PCT) plays an important role as the factor to reflect patients' inflammation or sepsis degree.In order to reach a low concentration detection of PCT with label free method,proposed was a type of PCT immunosensor based on excessively tilted fiber grating (Ex-TFG) which is insensitive to temputere but sensitive to refractive index.Staphylococcus aureus Protein A (SPA) was used to modify the surface of Ex-TFG,then highly purified PCT monoclonal antibodies (MAbs) were immobilized on Ex-TFG's surface through SPA molecules,so as to form the immunosensor which is specific to PCT.Experimental results show that the wavelength shift is about 13 pm when PCT concentration is 0.5 ng/mL,and it becomes to be 125 pm with the concentration of PCT increasing to 200 ng/mL.What's more,the immunosensor becomes saturated at ～ 1 000 ng/mL,and the corresponding wavelength shift is about 150 pm.Finally,by fitting the experimental data,it demonstrats that the fitting line meets the Langmuir model function with a corelated coefficient of 0.98.