A three-site recognition cytosensor based on multi-active AuIrPt polyhedral nanozymes for detection of CTCs

We developed a novel electrochemical cytosensor based on AuIrPt nanozymes and three-site recognition strategy for the detection of specific CTCs. Using pluronic F127 as the organic framework, new trimetallic AuIrPt nanozymes with exceptional multiple enzyme-like activities were synthesized, which could mimic the activities of three enzymes, SOD, POD, and CAT. Nanozymes linked with EpCAM (Epithelial cell adhesion molecule) aptamers served as signal tags to enhance sensitivity of the cytosensor, and anti-MUC1 (Mucin 1) and anti-EGFR (Epidermal growth factor receptor) antibodies for isolation and capture of the target CTCs, respectively. The AuIrPt nanozymes could approach the sensing interface and generate obvious currents through their exceptional catalytic activity only when all three proteins (MUC1, EpCAM, and EGFR) were simultaneously expressed on the cell membrane. Benefiting from the aforementioned advantages, our cytosensor could accurately distinguish between target cells and other cancer cells with a wide concentration range from 5 to 1 × 106 cells mL−1 and a low detection limit of 2 cells mL−1. Notably, the biosensor could assay target CTCs in complex whole blood matrixes, validating its resistance to interference and utility. By combining catalytic nanomaterials and three-site recognition strategy, a sensitive, accurate, and stable novel sensing platform has been developed, promising to facilitate the application of CTCs in early cancer screening.