Biomedical Engineering Reference
In-Depth Information
Cell seeding
Inlet channels
Main
channel
Cell-adhesive microtracks
a
X
Y
Perfusion
channel
200 µm
Cell fusion
Day 7
Cell-repellent coating
Long-term perfusion and differentiation
b
Myotubes
50 µm
AChR
Longitudinal flow
Agrin
Focal stimulation with agrin
c
Orthogonal flow
50 µm
FIGURE 6.13
A.microluidic.device.to.study.muscle.cell.differentiation.and.neuromuscular.synapto-
genesis..(From.Tourovskaia,.A.,.Figueroa-Masot,.X..and.Folch,.A.,.“Long-term.microluidic.cultures.
of.myotube.microarrays.for.high-throughput.focal.stimulation,”.
Nat. Protoc.
.1,.1092,.2006..Figure.
contributed.by.Anna.Tourovskaia.)
ready to be focally stimulated with agrin or other synaptogenic compounds (
Figure 6.13c
). he
formation of these AChR clusters of convoluted morphologies—nicknamed “pretzels”—(similar
to the “pretzels” found in vivo) is indicative of an advanced stage of diferentiation.
6.3 Cell-Cell Communication
Cells send signals to other cells to command, alert, or coordinate a variety of cellular behaviors.
Oten, these signals are sent by direct membrane contact, such as through receptor activation
or the formation of synaptic contacts or gap junctions, so there is great interest in methods
that allow for placing pairs of single cells in direct contact, methods that modulate the physical
distance between two cell populations, and methods that simulate the presence of another cell
through a biomimetic microluidic device or surface micropattern.
6.3.1 Control of Cell-Cell Contacts at Single-Cell Scale
Chris Chen's laboratory, then at Johns Hopkins University, used in 2002 surface “bow tie”
micropatterns to control the amount of contact between two adhered endothelial cells, which
in turn inluences their cell division cycle (
Figure 6.14
). he substrates were prepared by micro-
luidic patterning of agarose (as a cell repellent, ~10 μm thick) on glass physisorbed with ibro-
nectin, to which cells adhered normally (
Figure 6.14a
). he area available for cells to attach was
restricted to a bow tie shape such that, if a pair of cells landed by chance on either side of the
bow tie micropattern, they were able to communicate only through the spatial restriction; the
