Carcinoembryonic antigen (CEA), serves as a broad-spectrum tumor marker, and plays an important role in reflecting the existence, therapeutic evaluation, development, monitoring and prognosis of many types of cancer. An electrochemical aptasensor was designed for CEA detection based on toehold-aided DNA recycling. A partially hybridized Probe-4 (i.e. P2/P3/P4) was self-assembled on the surface of a gold electrode serving as the sensing platform. For CEA detection, CEA can bind with aptamer and free probe-1 (P1) can hybridize with P4, triggering toehold-aided DNA recycling. This enables the hybridization of more probe-5 (P5) (labeled with methylene blue (MB)) with P4, causing more methylene blue (MB) to be brought close to the electrode surface. An amplified current signal was thus generated due to more MB in the electrode surface. The proposed design showed good linearity between current response and log CEA concentration ranging from 0.1 to 50 ng·mL-1, with a detection limit of 20 pg mL-1. This aptasensor also showed high specificity for CEA detection, and was successfully used in spiked biological samples.

中文翻译：

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基于脚趾辅助DNA回收信号扩增的癌胚抗原电化学适体传感器的构建。

癌胚抗原（CEA）是一种广谱肿瘤标志物，在反映多种类型癌症的存在，治疗评估，发展，监测和预后方面起着重要作用。电化学适体传感器被设计用于基于脚趾辅助DNA循环的CEA检测。将部分杂交的Probe-4（即P2 / P3 / P4）自组装在用作传感平台的金电极表面上。对于CEA检测，CEA可以与适体结合，而游离探针1（P1）可以与P4杂交，从而触发脚趾辅助DNA的回收利用。这使得更多的探针5（P5）（用亚甲基蓝（MB）标记）与P4杂交，从而使更多的亚甲基蓝（MB）靠近电极表面。由于电极表面中更多的MB，因此产生了放大的电流信号。拟议的设计显示电流响应与log CEA浓度在0.1至50 ng·mL-1之间具有良好的线性，检出限为20 pg mL-1。该适体传感器还显示出对CEA检测的高度特异性，并已成功用于加标生物样品中。