Microfluidic Chip-Based Circulating Tumor Cell Isolation Device for Minimal-Invasive Liquid Biopsy

Circulating tumor cells (CTCs) are valuable biomarkers for early cancer diagnosis, metastasis monitoring and therapeutic response evaluation. However, CTCs are extremely scarce in peripheral blood, and the isolation of intact CTCs with high purity remains technically challenging for conventional enrichment methods. This work develops a label-free microfluidic device that isolates CTCs based on the differences in cell size, deformability and hydrodynamic properties. The chip contains cascaded curved microchannels and deterministic lateral displacement arrays, which separate tumor cells from abundant leukocytes and erythrocytes without antibody modification. The entire workflow requires only a small volume of peripheral blood and completes enrichment within 30 minutes. Recovered CTCs retain viability and can be subjected to downstream immunofluorescence staining and single-cell gene sequencing. Testing with clinical blood samples from lung cancer patients shows satisfactory enrichment efficiency. The principal limitation is the lower capture performance for CTC clusters with heterogeneous mechanical properties. This microfluidic isolation device facilitates liquid biopsy workflows and supports non-invasive longitudinal tumor monitoring.