Objective To construct the new technique of electrochemical label‐free immunosensor based on GO‐ECR for the detection of CA19‐9 . Method Graphene prepared from chemical routine was used to modify glassy carbon electrode ,and then the GO‐ECR film modified electrode was fabricated by cy‐clic voltammetry deposition . With the help of EDC and N HS ,anti‐CA19‐9 w as immobilized on the modi‐fied electrode through covalent bond . The fixed anti‐CA19‐9 reacted with CA19‐9 to form immunocom‐plex . Using K3 [Fe(CN )6 ] as electrochemical probe ,the variable current response before and after the immobilized CA19‐9 implied the concentration of CA19‐9 . And the different current responses were used to specifically quantify the concentrations of CA19‐9 . Result The electrochemical immunosensor can be applied to accurately detect the CA19‐9 ,and the clinical serum CA19‐9 concentration can also be precisely detected . Conclusion The constructed electrochemical label‐free immunosensor based on GO‐ECR for the detection of CA19‐9 show s the characteristics of high accuracy and specificity .%目的：构建石墨烯‐依来铬青蓝R（GO‐ECR）免标记电化学免疫传感器高灵敏检测CA19‐9的新技术。方法化学法合成氧化石墨烯并滴涂于电极表面，通过循环伏安法电沉积制作GO‐ECR修饰玻碳电极，在偶联剂EDC和N HS作用下以共价键合方式将CA19‐9抗体固定于修饰电极表面，固定的抗体与CA19‐9发生免疫反应形成抗原‐抗体复合物。铁氰化钾溶液作为检测探针，对比免疫反应前后铁氰化钾响应信号的差异，利用信号降低程度与CA19‐9浓度正相关，实现对CA19‐9的特异性高灵敏检测。结果该电化学免疫传感器检测CA19‐9的线性范围为0．05～500 U／mL ，检测限为0．01 U／mL ，且能准确测定临床血清样本CA19‐9的浓度。结论构建的GO‐ECR免标记电化学免疫传感器可以简单、准确、特异地检测CA19‐9。
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