Artificial Antibody with Site-Enhanced Multivalent Aptamers for Specific Capture of Circulating Tumor Cells.

Isolation of circulating tumor cells (CTCs) from blood holds great potential to diagnose cancers and discover therapeutic targets. Herein, we reported a novel kind of artificial antibody, the cell-imprinted hydrogel with site-directed modification of aptamers (APT-CIH) to achieve the specific capture of CTCs. Cell-imprinted sites not only could be used to recognize target cells but also could be used as efficient scaffolds for assembling aptamers to enhance the capture efficiency and selectivity. Due to the synergistic effect of conformation recognition and multivalent interaction between the aptamers and target cells, APT-CIH showed high capture efficiency and selectivity to SMMC-7721 cells. In the coexistence of the 1000 times leukemia Jurkat cells, the enrichment factor of APT-CIH could reach as high as 21.6 ± 3.1 toward target cells, while that relied only on cell imprinting or aptamer affinity was 8.1 ± 5.0 or 10.1 ± 1.3, respectively. Furthermore, the capture efficiency could reach 58.2% ± 10.9% with 1000 SMMC-7721 cells spiked in 1 mL of blood. Moreover, 92% of the captured cells could be released, beneficial to carry out further biological and clinical study of CTCs. These results demonstrated that APT-CIH might have great potential in CTCs analysis.