Biomedical Engineering Reference
In-Depth Information
b
3D Configuration
a
2D Configuration
Cell population
Basal surface
Single cell
Focal adhesion Complex
Actin
Actin
stress fiber
Integrin
Integrin
Plasma membrane
Plasma membrane
Fig. 11.3
The effects of (
a
) two-dimensional (2D) and (
b
) three-dimensional (3D) confi guration
on the scale of a single cell and a cell population. The
bottom
illustrations are typical adaptive
responses of actin cytoskeletal system respond to the topographical features
focal adhesions on the basal surface. In contrast, the 3D scaffold confi guration is
used to guide actin stress fi bers and focal adhesions to dispersal. Furthermore, the
confi guration of a 3D structure is preferable when we need additional effects, such
as the control of diffusive transport (Adachi et al.
2006
; Shin et al.
2011
) and that of
interstitial fl ow (Kamioka et al.
2012
), beyond the direct effects of the micro-/
nanotopography.
11.3.1.3
Topography on the Scale of Sub-micrometers to Ten
Micrometers: Constraints on the Actin Cytoskeleton
The size of endogenous actin fi laments is on the scale ranging from sub-micrometers
to ten micrometers. Thus, topographical features sub-micrometers to ten microme-
ters in size work as direct constraints on actin fi laments. The process has long been
recognized as “contact guidance” (Bettinger et al.
2009
; Clark et al.
1990
; Oakley
and Brunette
1993
). As described in Sect.
10.6
of Chap.
10
, contact guidance
explains that the probability of actin fi laments traversing the obstacles is low due to
the mechanical restriction of the cytoskeleton. The contact guidance has been well
characterized by means of simple synthetic 2.5D micro-topographical features,
such as parallel ridges and grooves (Clark et al.
1990
; Crouch et al.
2009
; Ohara and
Buck
1979
; Zhu et al.
2004
; Bettinger et al.
2008
; Kaiser et al.
2006
; Tan and
