Microfluidic biochip for target tumor cell and cell-cluster sorting

This study designed an integrated microfluidic biochip to separate target tumor cells and their clusters from whole blood. The first-stage sorting mechanism in the top channels was based on sorted object size by taking advantage of the in-series Deterministic Lateral Displacement (DLD). In the downstream bottom channel, the target tumor cells/cell clusters were trapped and sorted out by the antibody-coating lateral filter at the second stage. In the top-channel DLD cluster-sorting session, U-shaped pillars and two-section continuous sorting areas with different critical diameters could disperse the displacement of target tumor clusters and effectively rotate the non-symmetry tumor clusters to increase their effective size. In the downstream bottom channel, the selective coating on the lateral filter posts was used to coat antibodies exclusively on the side surface of micro-pillars to prevent clogging. The suspension of solid tumors from the 4T1-bearing BALB/c mouse was spiked in the blood from the same mouse to serve as the experimental blood sample. The DLD cluster-sorting session recovered 88.58% of tumor cell clusters with a purity of 92.20%. The lateral filter in the bottom chip captured 89.54% of tumor cells with a purity of 89.44%. This two-stage microfluidic chip developed in this research aims to study CTC clusters in cancer research and clinical applications.