Dual-aptamer-based colorimetric assay for the accurate identification of circulating tumor cells via Fe3O4@Pt NP nanozymes and G-quadruplex/hemin for signal amplification

The precise identification and detection of circulating tumor cells (CTCs) is significant for the early diagnosis and prognostic treatment of cancer. However, it remains a challenge to detect CTCs with high sensitivity and specificity. In this study, a colorimetric sensor for the analysis of CTCs was constructed based on dual-aptamer recognition and core (Fe3O4)–shell (Pt) nanoparticle (Fe3O4@Pt NP) nanozymes coupled with a G-quadruplex as a signal transducer/amplifier. The results show that the linear range of the designed colorimetric sensor is 50–4000 cells and the detection limit is 4 cells. The constructed aptasensor could be extended to identify various CTCs by changing the aptamers, and holds great potential in precise tumor diagnosis.