A microfluidic device for enhanced capture and high activity release of heterogeneous CTCs from whole blood

Circulating tumor cells (CTCs) are tumor cells that spontaneously detach from the primary focus, and early detection and characterization of CTCs is vital for cancer diagnosis and appropriate treatment. Current methods commonly use EpCAM to capture CTCs, but this results in a loss of information on other CTC subsets (EpCAM-negative cells) due to the heterogeneity of CTCs. Here, we report a novel microfluidic device that integrates the capture and release of heterogeneous CTCs directly from whole blood. A spiral chip was designed for the separation of differently sized cells, and larger CTCs were effectively separated from smaller blood cells with a 98% recovery rate. CD146-containing magnetic beads were used to complement the EpCAM-based CTC capture methods, and the capture efficiency of Fe₃O₄@Gelatin@CD146/EpCAM increased by 20% over Fe₃O₄@Gelatin@EpCAM. Finally, MMP-9 was employed to release CTCs with high efficiency and less damage by degrading gelatins on the surface of Fe₃O₄. The established method was successfully applied to CTC capture and release in a simulated patient's whole blood. The developed method achieved enhanced capture and high activity release of heterogeneous CTCs with less interference by blood cells, which contributes to the early detection and clinical downstream analysis of CTCs.