Biomedical Engineering Reference
In-Depth Information
FIGURE 9.2: Orientation of cell migration along matrix fiber topology. Both
on 2D (A) and within 3D matrix (B), the overall number of basic fibers re-
mains fixed with respect to the standard simulations of Figure 9.1, while their
percentage along the x-axis is increased. The alignment of the matrices is
quantified by the alignment index N align , defined in (9.5), which is 0 in the
case of isotropic networks (already analyzed in the previous section) and 1
for fully aligned ECMs. The wind-rose graphs show 10 randomly chosen cell
tracks over 12 h. The simulation-based images show instead cell morphologies
in the case of completely aligned matrices.
networks (already discussed in the previous section) and 1 in the case of fully
aligned matrices.
As a result, for both 2D and 3D migration, the paths gradually adapt
toward anisotropic random walks, in particular, the directional cell motion
increases toward the principal direction of alignment; see Figure 9.2(A-B).
Interestingly, the cells' nal average velocity and MSD remain constant despite
increasing substrate orientation, with very similar values for both 2D and 3D
conditions. However, the cells' 2D and 3D directed motile behavior in response
to fiber distribution directly correlates with a strong increase in time (up to
5 h) that cells are able to perform persistent movement (i.e., without back-
and-forth movements), as captured by the plots in Figure 9.3. Therefore, ECM
geometry and architecture directly impact the migration pattern of individual
cells. The directionality of cell movement is here not introduced a priori, but is
 
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