Rapid Isolation and Biophysical Characterization of Circulating Tumor Cells with Microfluidic Vortex Technology

Disseminated and circulating tumor cells are key players of metastatic cancer and have high diagnostic and prognostic value. These cells may often accumulate and persist in body fluids—such as in pleural effusions or blood—which are minimally-invasive sources for patient sampling. However, tumor cells are relatively scarce and must typically be enriched from a large background of blood cells. An inertial microfluidic device was developed to specifically trap and concentrate large tumor cells in stable microvortices which form under high flow rates. The novel label-free Vortex platform was optimized to isolate large rare cells at high efficiency (up to 80%), purity (10-80%), concentration (~200 μL volume), and viability (>80%) in a short time period (<30 min). Enriched cells from pleural effusions and blood are made freely available and compatible for a variety of downstream analysis techniques. This work highlights the purification of disseminated tumor cells from pleural effusions, yielding i) a greater than 65-fold enrichment of malignant cells for a significant reduction in cytology slide background that facilitates ease of diagnostics by pathologists, and ii) an increase in area under the receiver operating characteristic curve from 0.90 to 0.99 for the detection of point mutations which may aid in personalized medicine. Isolation of circulating tumor cells from blood was also demonstrated and applied toward i) immunofluorescent staining to achieve a 5.7x higher success rate of tumor cell detection than the existing CellSearch gold standard, and ii) mechanophenotyping of cells by deformability as a truly label-free and potentially superior approach over immunostaining (93.8% vs. 71.4% success rate) for enriching and enumerating cells to determine cancer patient prognosis. The presented platform technology is a means for rapidly providing valuable information about patient state that is useful for informed cancer treatments and monitoring of disease progression