Fig. 4. Isolation of CTCs from patients with localized and metastatic prostate cancer.

a Example CTCs (bright green dots) captured from whole blood of localized cancer patients using an anti-EpCAM antibody-activated microfluidic device. A magnified single captured intact CTC is shown in the inset. The scale bar is 8 μm. b Fluorescent images of a captured CTC (top panel) and a WBC (bottom panel) revealed the staining of their nuclei (blue, DAPI+ for CTC and WBC), cytoplasmic cytokeratin (red, CK+ for CTC), CD45 (red, CD45+ for WBC), and EpCAM (green, EpCAM+ for CTC and EpCAM− for WBC). The cytoplasmic-to-nuclear area ratio of the CTCs was ~1.6. The scale bar is 20 μm. c The developed device has shown to be efficient in capturing CTCs both from patients with localized (using anti-EpCAM, anti-PSA, and anti-PSMA antibodies in Patients 1–3 and using anti-EpCAM in Patient 4) and metastatic prostate cancer (using anti-EpCAM antibodies in Patients 5 and 6). d The size distribution of captured CTCs revealed that, on average, the size of CTCs from localized cancer is ~16 μm in diameter, whereas the size of CTCs from metastatic cancer is ~19 μm in diameter. *Statistically not significant at P < 0.05 using t test. e Nonspecific binding of WBCs in EpCAM antibody-activated microfluidic devices was ~10 times less than that of the bare (untreated) chips due to hydrophilicity of the high-density antibody layer on the glass substrates (n = 6). Error bars represent the mean ± S.D