Biomedical Engineering Reference
In-Depth Information
a
PDMS channel
c
Polycarbonate
membrane
PDMS channel
b
Cell culture
within microchannel
d
500 µm
Day 0
MDA-MB-231 cells
COS7 cells
Day 3
FIGURE 2.41
Hydrodynamic.trapping.of.cells..(From.Yu-suke.Torisawa,.Bor-han.Chueh,.Dongeun.
Huh,.Poornapriya.Ramamurthy,.Therese.M..Roth,.Kate.F..Barald,.and.Shuichi.Takayama,.“Eficient.
formation.of.uniform-sized.embryoid.bodies.using.a.compartmentalized.microchannel.device,”.
Lab
Chip
.7,.770,.2007..Reproduced.with.permission.from.The.Royal.Society.of.Chemistry..Figure.con-
tributed.by.Shu.Takayama.)
With the proper design, low patterns may be established within the channel to deposit the cells
at particular locations. Shuichi Takayama and colleagues from the University of Michigan at Ann
Arbor have sandwiched porous membranes between two microchannels to micropattern the attach-
ment to cells within microchannels (
Figure 2.41
). he low is forced to go from the upper micro-
channel into the lower microchannel through the membrane, but the cells (which do not it through
the pores) get hydrodynamically trapped at the membrane surface, which serves as a long-term
cell culture surface. When MDA-MB-231 cells and COS7 cells were simultaneously patterned in a
coculture, the cells self-aggregated and formed a spheroid while maintaining the shape of the letters
(
Figure 2.42d
). A very similar idea had been used back in 1987 by Friedrich Bonhoefer's group at
the Max Planck Institute (Tübingen Germany) to immobilize cell membrane fragments in stripes,
the basis for the famous “stripe assay” for axon guidance studies (see
Figure 6.41
in Section 6.5.1.1).
2.6.2.7 Selective Physisorption on a Microtextured Surface
Alan Rudolph and coworkers at the Naval Research Laboratory in Washington, DC fabricated
in 1996 microtextured surfaces with deep trenches in a variety of biomedical polymers and
selectively physisorbed proteins onto the mesas by carefully dipping the microstructures in a
protein solution. As a result, only the mesas, not the trenches, were coated with protein solu-
tion. With this method, they demonstrated the selective attachment of NCTC-929 cells onto
