Figure 3
(A) DiD-labelled MDA-MB-231 cell (red CTC) arrest at the bifurcation of the Y-microchannel covered with calcein-labelled primary HUVEC cells (green endothelial monolayer). (B) Representative image of GFP-labelled MDA-MB-231 cells (green CTC) perfused in mice before direct labelling of the vasculature of the lung with DiI dye (red blood vessels), illustrating the CTC arrest at the carina of vessel bifurcations (arrowhead) in an in vivo preclinical model. The size bar in panel A is valid also for panel B. (C) GFP-labelled MDA-MB-231 cells embedded in three different types of fluids: non-conditioned basal culture media (upper panels), 0.5% Methylcellulose (middle panels), and FBS (foetal bovine serum; lower panels), showing improved CTC arrest at the low-velocity areas of the carina as the viscosity of the medium is increased. (D) Numerical representation of the low-velocity areas at the carina of the bifurcations depending on the viscosity of the medium, as calculated in the simulations. The insets correspond to the graphical representation of the areas of low velocity at different viscosity values illustrating the enlarged area as the viscosity is increased (the dashed black line marks the boundary for the lowest viscosity). The viscosity of the three different media included in panel (C) were numerically checked and their values (1*, non-conditioned culture medium; 2*, FBS (foetal bovine serum); and 3*, 0.5% Methylcellulose) and corresponding graphical low-velocity areas are plotted in red. (E) Quantification of CTC arrest calculated by integrated intensity, is graphically described. Statistical differences were found between the groups, seeing higher levels of CTC arrest with higher viscosity levels (t-test, ***p < 0.001; R2 = 0.99).
