Biomedical Engineering Reference
In-Depth Information
extent of branching and conirmed that mouse mammary epithelial tubules initiate branching
at sites with a local minimum in concentration of transforming growth factor-β, an autocrine
inhibitory morphogen. As seen in the cell micropatterns of
Figure 7.23b
,
e
,
and
g
, branching is
most prominent at the edges, where the difusible inhibitor concentration secreted by the cells is
lowest (compared with
Figure 7.23c
,
d
,
and
f
, respectively). he invasion of epithelial cells into
(a)
1.00
0.79
0.59
0.38
0.18
-0.03
(b)
(c)
(f )
1.00
0.75
0.50
0.25
0.00
-0.25
0.20
(d)
(g)
(e)
(h)
0.15
0.10
0.05
0.00
FIGURE 7.24
Correlation.between.proliferation.and.mechanical.stress.in.microfabricated.multicel-
lular.islands..Scale.bars.are.100.
μ
m..(a).A.contracting.monolayer.modeled.in.inite.element.model.
(FEM)..(b).FEM.calculations.of.relative.maximum.principal.tractional.stress.exerted.by.cells.in.a.
small. square. island.. Cell. proliferation. on. a. symmetric. cell. annulus. shown. in. (c). phase. contrast,.
(d) FEM.results,.(e).and.colorimetric.stacked.image..In.colorimetric.stacked.images,.a.pixel.value.
of.0.20.indicates.that.20%.of.cells.at.that.location.proliferated..Cell.proliferation.on.an.asymmetric.
cell.annulus.shown.in.(f).phase.contrast,.(g).FEM.results,.and.(h).colorimetric.stacked.image..(From.
Celeste.M..Nelson,.Ronald.P..Jean,.John.L..Tan,.Wendy.F..Liu,.Nathan.J..Sniadecki,.Alexander.A..
Spector,.and.Christopher.S..Chen,.“Emergent.patterns.of.growth.controlled.by.multicellular.form.
and. mechanics,”.
Proc. Natl. Acad. Sci. U. S. A.
. 102,. 11594-11599,. 2005.. Copyright. (2005).
National.Academy.of.Sciences,.U..S..A.)
