Biomedical Engineering Reference
In-Depth Information
features of the biomaterial surface, which may be tuned through
control of the electrospinning conditions. Specific features that are
considered in this section are 1) the degree of fiber alignment, 2)
the diameter ofindividual fibers, and 3) theroughness of fibers.
15.2.1
Effect of Electrospun Fiber Alignment on Cell
Morphology
Simple electrospinning onto a stationary target produces a random
distribution of fiber orientations, while the deposition onto a rotat-
ing drum,
11
rotating disc,
12
or between two grounded surfaces
13
can result in moderate to very high degrees of fiber alignment.
Although seemingly similar, mammalian cells respond differently to
these surfaces. For example, the projected cell area of osteoblasts
1
and fibroblasts
11
is diminished on random electrospun meshes. In
contrast, when the fibers are aligned these cells selectively spread
parallel to the direction of fiber alignment (Fig. 15.1). Similarly,
embryonichippocampalneuronsanddorsalrootganglia(DRG)have
been reported to extend axons
14
and neurites,
15
respectively, along
fibers. Further, when these fibers are aligned a higher percentage
ofembryonicneuronsexhibitpolarization,whilethelengthsofDRG
neurons isincreased.
Two theories can explain these two effects of fibers on cell
morphology. The first is related to the phenomenon of contact
Figure 15.1.
Cells on (a) random and (b) horizontally aligned fibers. The
fiber alignment guidescell alignment.
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