Biomedical Engineering Reference
In-Depth Information
the time-lapse series in
Figure 6.44e
) or when neurons from a myosin IIB knockout mouse are
used (
Figure 6.44c
and the time-lapse series in
Figure 6.44f
). Blebbistatin does not afect the
outgrowth of myosin IIB knockout mouse axons (
Figure 6.44g
).
6.5.1.2 Axon Guidance by Microtopography
In 1997, a collaborative Scottish team led by Stephen Britland at the University of Glasgow and
by Colin McCaig at the University of Aberdeen in Scotland (United Kingdom) performed the
irst study of the efects of microtopography on axon growth (
Figure 6.45
). hey observed that
the axons of
Xenopus
and rat hippocampal neurons could be guided by parallel quartz grooves
as shallow as 14 nm (much shallower than the axon!) and as narrow as 1 μm.
If the objective is to guide axons, why not use microchannels directly so the axons are con-
ined by four walls? For the same price, one could incorporate many connections, control perfu-
sions, and produce gradients … In 2001, the laboratory of Hiroyuki Fujita at the University of
Tokyo demonstrated basic axon growth in the irst microluidic neural guidance device, which
was built by sot-lithographic techniques from a SU-8 master (
Figure 6.46
).
In 2003, Noo Li Jeon's group at the University of California designed a microfabricated
“Campenot chamber” that allows for luidically isolating the somas from the neurites in a
neuronal culture (
Figure 6.47
). In traditional Campenot chambers, which are made of Telon,
grooves are scratched on collagen-coated plastic so that axons can grow under the Telon bar-
rier; unfortunately, the scratches are dimensionally undeined, the Telon needs to be sealed
with an unreliable vacuum grease (only ~30% of the devices work), and the Telon is opaque (so
it is not compatible with live cell imaging). Jeon's microfabricated Campenot chamber is trans-
parent and consists of a set of parallel grooves that guide the growth of axons by topographi-
cal guidance from the somal chamber to the neuritic chamber (ater ~4 days in culture). If a
1-µm-wide, 320-nm-deep grooves
1-µm-wide, 500-nm-deep grooves
Xenopus
neurons
25 µm
a
b
FIGURE 6.45
Axon.guidance.by.microtopography..(From.Ann.M..Rajnicek,.Stephen.Britland,.and.
Colin.D..McCaig,.“Contact.guidance.of.CNS.neurites.on.grooved.quartz:.Inluence.of.groove.dimen-
sions,. neuronal. age. and. cell. type,”.
J. Cell Sci.
. 110,. 2905-2913,. 1997.. Figure. contributed. by.
Stephen.Britland.)
a
b
PC12 cells
30 µm
20 µm
FIGURE 6.46
Microluidic. channels. used. as. topographic. guideposts.. (From. Laurent. Griscom,.
Patrick.Degenaar,.Bruno.LePioule,.Eichi.Tamiya,.and.Hiroyuki.Fujita,.“Cell.placement.and.neural.
guidance.using.a.three-dimensional.microluidic.array,”.
Jpn. J. Appl. Phys.
.40,.5485-5490,.2001..
Reprinted.with.permission.from.the.Japan.Society.of.Applied.Physics.)
