Fig 2: Capture of CTCs using the custom polymeric CTC chip. (A) Protocol for CTC capture with the custom CTC chip. Peripheral blood samples (5 ml) were collected from patients into tubes containing ethylenediaminetetraacetic acid. Samples were centrifuged at 300 × g for 5 min at 4°C. After removing plasma, cellular components including buffy coat were dissolved in 1.5 ml PBS. Processed samples were transferred to the CTC chip using automatic syringes. Micropoles on the chip were coated with EpCAM antibodies to capture CTCs. Captured CTCs were stained with CK19 and CD133 or other antibodies. (B) Representative images of the captured CTCs and their schemes. HCT116 cells were captured (arrows) at the micropoles coated with EpCAM antibodies and the cells were stained with DAPI and CK19 antibodies (upper panels). HCT116 cells mixed with blood from a healthy donor were captured. All cells were stained with DAPI, but only HCT116 cells were stained with anti-CK19 (middle panels). CTCs in patient blood were captured. All cells were stained with DAPI, but only the CTCs were stained with anti-CK19 (lower panels). Scale bar, 50 µm. CTC, circulating tumor cells; WBC, white blood cell.