Highly Efficient Isolation of Circulating Tumor Cells Using a Simple Wedge-Shaped Microfluidic Device.

Objective: We have developed a novel simple wedge-shaped microfluidic device for highly efficient isolation of circulating tumor cells (CTCs) from cancer patient blood samples.

Methods: We used wet chemical etching and thermal bonding technologies to fabricate the wedge-shaped microdevice and performed optimization assays to obtain optimal capture parameters. Cancer cells spiked samples were used to evaluate the capture performance. Clinical assays were performed to isolate and identify CTCs from whole blood samples of patients with liver, breast, lung, and gastric cancer.

Results: Outlet height of 5.5 μm and flow rate of 200 μL/min were chosen as the optimal CTC-capture conditions. This method exhibited excellent isolation performance (more than 85% capture efficiency) for four cancer cell lines (HepG2, SKBR3, A549, and BGC823). In clinical assay, the platform identified CTCs 5 in 6 liver (83.3%), 8 in 10 breast (80%), 5 in 8 lung (62.5%), 5 in 9 gastric (55.6%) cancer patients, and only 1 in 25 healthy blood samples (4%).

Conclusion: Our wedge-shaped microfluidic device had several advantages, including relatively simple fabrication, high capture efficiency, simple sample processing steps, and easy observation.

Significance: This method had successfully demonstrated the clinical feasibility of CTC isolation and shown a great potential of clinical usefulness in monitoring tumor prognosis and guiding individualized treatment in the future.