溶胶-凝胶非标记CA15-3免疫传感器的研制与应用

A Sol-gel-derived Non-labeled Immunosensor for Antigen CA15-3

采用溶胶 -凝胶技术将乳腺癌抗体固定于电极表面 ,研制成用于检测乳腺癌抗原的非标记型溶胶 -凝胶 -抗体膜免疫传感器 ;用循环伏安法对电极的修饰过程进行表征 ,同时对乳腺癌抗原定量检测的可行性进行了探讨 ;随着抗体与抗原特异性反应的进行 ,形成的抗体 -抗原免疫复合物使膜电位发生变化 (ΔV) ,该变化的大小与溶胶 -凝胶 -抗体膜表面免疫反应进行的程度相关 ;本文以此为依据对CA15_3进行检测 ,在5～240U/mL范围内 ,ΔV与lgcCA15_3 呈良好的线性关系 ,线性相关系数r=0.998;该传感器响应迅速 ,灵敏度高 ,稳定性好 ,于4℃干态保存30d ,其响应信号基本不变。

A new type of non-labeled immunosensor was prepared for the determination of breast cancer antigen CA15-3(Ag). The breast cancer antibody(Ab) was first encapsulated in a tetraethylorthosilicate(TEOS) sol-gel film, and the sol-gel-Ab layer was then coated onto the surface of a platinum-disk electrode. The electrochemical characteristics of the modified electrode at different stages of modi-fication was studied by cyclic voltammetry(CV) in a solution of K3Fe(CN)6(5 mmol/L)-KNO3(0.1mol/L)-PBS(0.1 mol/L). With the progress of the antibody-antigen reaction, the immune com-plex of Ab-Ag brings about a change of the membrane potential ΔV. The magnitude of this changeis pertinent to the extent of the immune reaction. This correlation has been applied to the quantitativedetermination of antigen CA15-3. ΔV and lg c show a good linear correlation in the range of 5～240U/mL with a correlation coefficient of 0.998. The effects of pH and incubation time have been studied.The sensor has a fast response, high sensitivity, good reproducibility and prolonged stability for 30 daysat 4 ℃.