Figure 1
From: The plasma protein fibrinogen stabilizes clusters of red blood cells in microcapillary flows
(a) A cluster of RBCs (above) and a single RBC (below) passing through a capillary of a mouse (see SM1 for an online video). The RBCs are imaged in a dorsal skinfold chamber using intravital fluorescence microscopy. To enhance the contrast, 0.05 ml 5% fluorescein-isothiocyanate (FITC)-labelled dextran was injected in vivo via the retrobulbary space. The effective dextran concentration in the vascular network is well below any significant effect of aggregation. The images are colourised. (b) A schematic drawing of the microfluidic device and shadowgraph snapshots of clusters of RBCs in the microcapillaries. The microfluidic device includes 30 parallel channels of rectangular cross-section 8.5 μm (width) and 4.5 μm (height). The images are recorded using a high-speed camera and the flow velocity and distribution of cells flowing through the observed section of the channels are determined (i.e., the numbers of single cells or clusters of different lengths (2, 3, 4, 5 or more cells) are counted). (c) A snapshot of the steady-state numerical results regarding the effect of intercellular surface energy due to fibrinogen on RBC organisation in a channel with a width w = 4.5 μm. From top to bottom: ε = 0, ε = 1.78, ε = 3.56 and ε = 4.89 μJ/m2 correspond to fibrinogen concentrations of 0, 1, 4 (still in the physiological range) and 6.5 mg/ml, respectively. (d) The same as in (c), but a channel of width w = 12 μm was used.
