Herein, based on a dual-recognition strategy and BSA@Ag@Ir metallic-organic nanoclusters (BSA@Ag@Ir MONs), a highly specific and sensitive cytosensor was developed for detecting circulating tumor cells (CTCs). To amplify current signal, novel BSA@Ag@Ir MONs with outstanding catalytic activity and huge specific surface area were synthesized, and conjugated with hairpin DNA strands as signal probes. Orion carbon black 40 (Ocb40)//AuNPs were firstly used to modify electrode to increase its conductivity and surface area. Moreover, the dual recognition strategy based on DNA proximity effect was designed to improve the specificity of cytosensor. When two capture probes respectively bound to two adjacent membrane markers of target cells, the probes could form the associative toehold through the proximity effect to capture the signal probes. Only CTCs simultaneously expressing two membrane markers could be captured and generate current responses. The developed cytosensor could detect CTCs in the range of 3 - 3 × 10⁶ cells mL^-1 with a detection limit of 1 cell mL^-1. Notably, the cytosensor could accurately identify CTCs even in whole blood. Therefore, this cytosensor has great potential for application in biological science, biomedical engineering and personalized medicine.

在此，基于双重识别策略和BSA @ Ag @ Ir金属有机纳米簇（BSA @ Ag @ Ir MONs），开发了一种高度特异性和灵敏的细胞传感器，用于检测循环肿瘤细胞（CTC）。为了放大电流信号，合成了具有出色催化活性和巨大比表面积的新型BSA @ Ag @ Ir MONs，并与发夹DNA链偶联作为信号探针。Orion炭黑40（Ocb40）// AuNPs首先用于修饰电极，以增加其电导率和表面积。此外，基于DNA邻近效应的双重识别策略被设计来提高细胞传感器的特异性。当两个捕获探针分别与靶细胞的两个相邻膜标记物结合时，这些探针可以通过邻近效应形成缔合点，以捕获信号探针。只有同时表达两个膜标记的CTC才能被捕获并产生电流响应。研发的细胞传感器可以检测3-3×10范围内的CTC^6个细胞^-1毫升，检测限为1个细胞^-1毫升。值得注意的是，即使在全血中，细胞传感器也可以准确识别CTC。因此，这种细胞传感器在生物科学，生物医学工程和个性化医学中具有广阔的应用前景。