A signal‐off aptasensor was described based on well‐designed aptamer‐ Cu 3 (PO 4 ) 2 hybrid nanoflowers&graphene oxide composites ( aptamer‐Cu 3 (PO 4 ) 2 HNF&GO ) as an effective sensing platform and molybdophosphate precipitation as the signaling element. The aptamer, as the bi orecognition unit grafted on aptamer‐Cu 3 (PO 4 ) 2 HNF&GO by the specificity of streptavidin and biotin, captured the carcinoembryonic antigen (CEA) through specific interaction. The molybdophosphate precipitation were formed by the reaction of the aptamer‐Cu 3 (PO 4 ) 2 HNF&GO with molybdate ( MoO 4 2− ). However, the CEA‐aptamer bioconjugate layer films not only hinder electron transfer on the sensing interface, but also impede the formation of molybdophosphate precipitation, resulting that the current signal significantly decreased. So, a simple aptasensor for CEA was constructed with high sensitivity and signal‐off model. Under optimal experimental conditions using square wave voltammetry (SWV), the response peak currents decreases linearly with the logarithm of CEA concentrations in the range from 10 fg mL ‐1 to 500 ng mL ‐1 . Also, the feasibility of its applications has also been demonstrated in the analysis of clinical serum samples.

中文翻译：

---

基于适体-Cu3（PO4）2杂种纳米花和氧化石墨烯的简单“信号关闭”电化学适体传感器，用于CEA检测

基于精心设计的适体-Cu 3（PO 4）2杂化纳米花与氧化石墨烯复合物（适体-Cu 3（PO 4）2 HNF＆GO）作为有效的传感平台，并以钼磷酸盐沉淀作为信号元件，描述了一种信号适体传感器。适体，作为通过链霉亲和素和生物素的特异性移植到适体-Cu 3（PO 4）2 HNF＆GO上的双认知单元，通过特异性相互作用捕获了癌胚抗原（CEA）。通过适体-Cu 3（PO 4）2 HNF＆GO与钼酸盐（MoO 4 2-）的反应形成了钼钼酸盐沉淀。然而，CEA-适体生物共轭层膜不仅阻碍了电子在传感界面上的转移，而且还阻碍了钼酸钼沉淀的形成，从而导致电流信号显着降低。所以，使用高灵敏度和信号关闭模型构建了一个简单的CEA自适应传感器。在使用方波伏安法（SWV）的最佳实验条件下，响应峰值电流随CEA浓度的对数线性下降，范围为10 fg mL-1至500 ng mL-1。同样，在临床血清样品分析中也证明了其应用的可行性。