Isolation of Circulating Tumor Cells from Peripheral Blood Samples of Cancer Patients Using Microfluidic Technology

The aim of the investigation was to study the potential of an innovative microfluidic technology for the isolation of circulating tumor cells (CTCs) from the peripheral blood samples of cancer patients.

Peripheral blood samples from 5 patients with disseminated malignant tumors of epithelial origin were processed with the use of the microfluidic technology (based on a specifically designed silicone chip). The cells were separated according to their density criterion based on the lateral migration of solid particles in a liquid due to inertial forces. With the help of the designed chip configuration, the cells over 13 μm in size which is larger than the standard size of blood cells were isolated. The resulting target cell fraction was stained by the Romanowsky-Giemsa method. Staining with the fluorescent Anti-Cytokeratin (CK3-6H5)-FITC antibody was carried out to confirm the epithelial nature of the cells, and the DAPI dye was used to contrast the nucleus. The blood of a healthy volunteer and tumor cells of the A549 line were used for the immunocytochemical studies.

The tumor cells in peripheral blood (in the number of 1 to 9) were detected in all 5 patients. CTC clusters of 2-5 cells were identified in blood samples from the patients with laryngeal cancer, non-small cell lung cancer, and floor of the mouth cancer. A bright saturated staining of the A549 tumor cells was obtained using the Anti-Cytokeratin (CK3-6H5)-FITC antibody, corresponding to the staining of the cytoskeleton of epithelial cells. Successful nuclear staining with DAPI confirmed that the isolated target cells are not damaged during microfluidic separation.

The microfluidic technology that has been used enables effective intact CTCs isolating from the peripheral blood of cancer patients. The epithelial nature of the isolated cells can be confirmed by immunocytochemical studies.