DNA fragment-assisted microfluidic chip for capture and release of circulating tumor cells

Circulating tumor cells are specifically referred as cells that detached from the primary tumor and are present in the bloodstream. They could be isolated from blood and used as representative biomarker for predicting cancer prognoses. Here, we developed a microfluidic chip with multiple curved channels, in which DNA fragments and antibody-based enrichment are exploited to capture circulating tumor cells in blood sample. By introducing DNA fragments as long tentacles, the active antibody could be extended into the microchannel stereoscopically, which could greatly increase the chances of adhesion in a multidirectional way and improve the capture efficacy. Several pivotal factors for cell capturing were optimized to the best state. Compared to conventional chips for planar capturing, the capture efficiency of MCF-7 cells was greatly increased from 37.17 to 85.10%. For the detection of MCF-7-containing artificial blood sample detection, the capture efficiency of tumor cells was about 74.19 ± 2.13%, which was obviously better than the result of flow cytometry (29.67 ± 4.02%). Captured cells were easily released from the surface of microfluidic chip with high cell viability, which could be investigated for the molecular analysis in the field of tumor diagnosis.