Fig. 2

Optimization assays of the microfluidic chip. A Flow chart of the optimization assays: (a) isolating BGC823 cancer cells from blood sample using the microfluidic chip: ➀ blood sample, ➁ sampling tube, ➂ waste tube, ➃ microfluidic chip, ➄ sampling needle, ➅ clamping device; (b) Identification cancer cells captured by the microfluidic chip with three-color immunofluorescence staining (Pan-CK, red; FITC-CD45, green; DAPI nuclear staining, blue) using fluoresce microscope (scale bar, 10×); and (c) Three-color immunofluorescence image of BGC823 cancer cell (CK+, CD45− and DAPI+) and WBC (CK−, CD45+ and DAPI+) in two different height areas (red area: about 1 μm; green area: about 4 μm) of the chip. Scale bar, 100 μm; B the capture efficiency of the microfluidic chip at different outlet heights (4, 5, 6, 7, 8 μm, respectively); C the capture efficiency of the microfluidic chip at different flow rates (50, 100, 200, 300, 400, 600, 800 μL/min). The error bar represents standard deviation from three repeats