Fig. 2

Aptasensors for the detection of MCF-7 CTCs. (A) Schematic diagram of the cell sensor and detection principle. Reprinted with permission from [51]. (B) Schematic diagram of the magnetic bead-assisted dual nanozymatic signal amplification method for CTC detection. Reprinted with permission from [52]. (C) The preparation process of Apt/Au@PbMo nanozyme signal amplification probe, the detection principle of cell sensor, the electrochemical signal generated by Au@PdMo nanozyme catalyzing H₂O₂, and the electrochemical reduction desorption mechanism of releasing CTCs. Reprinted with permission from [53]. (D) Principle of the portable photothermal cell sensor for direct capture and quantification of CTCs. Adapted with permission from [54]