DNA Bridged Polycrystalline Cu2+-NMOFs for Electrochemical Detection of Mesenchymal Circulating Tumor Cells

The analysis of mesenchymal circulating tumor cells (CTCs) with enhanced migratory is important in the diagnosis and metastasis prediction of cancer. In this work, an efficient electrochemical biosensor has been proposed for the sensitive analysis of mesenchymal CTCs. In our design, the capture antibody modified on the electrode surface can specifically recognize cell-surface vimentin, which is a specific biomarker of mesenchymal CTCs. In the meantime, polycrystalline Cu2+-NMOFs with excellent mimic peroxidase property assembled by functional nucleic acids are used as the signal probes. After capturing the mesenchymal CTCs with the capture antibody, the cholesterol-labeled functional nucleic acids modified on the Cu2+-NMOFs polycrystalline structures can serve as an anchor to insert into the cell membrane while bringing the polycrystalline Cu2+-NMOFs to the surface of the electrode. Consequently, an obvious enhanced signal is generated for sensitive quantitative of mesenchymal CTCs ranging from 2 × 101 to 104 cell mL−1 with a detection limit of 5 cell mL−1. Moreover, the biosensor can be applied to quantitative analysis of mesenchymal CTCs in blood samples of clinical bladder cancer patients with high selectivity and anti-interference ability, showing the great prospect for clinical cancer diagnosis.