Circulating Tumor Cells as a Biomarker of Response to Treatment in Patient-Derived Xenograft Mouse Models of Pancreatic Adenocarcinoma
Figure 1
CTC isolation using a microfluidic chip.
(A) Design of the CTC microfluidic chip with sinusoidally shaped capture channels and brightfield images of (B) the capillary tube inserted into the on-chip entry channel where whole blood enters the microfluidic chip, (C) sinusoidally shaped capture channels where anti-human EpCAM antibodies are immobilized for CTC capture, (D) exit channel, and (E) impedance sensor with two Pt electrodes located adjacent to the exit channel to detect released CTCs. (F) Cells captured from whole blood of PDX-tumor bearing mice visualized directly on the microfluidic chip following immunostaining with DAPI (blue), human cytokeratin 8/19 (CK, red), and mouse CD45 (green). The staining pattern of DAPI-positive, human CK-positive, and mouse CD45-negative is characteristic of human CTCs. (G) A rare contaminating mouse leukocyte bound non-specifically to the microfluidic chip stained DAPI-positive, human CK-negative, and mouse CD45-positive. Contaminating leukocytes were excluded from enumeration due to the high specificity of the electrical impedance detector for cancer cells.