Biomedical Engineering Reference
In-Depth Information
implanted in vivo, are prone to enzymatic degradation. Consequently, in
vascular graft applications, a scaffold made of only gelatin may not be
sufficient enough to provide adequate mechanical strength; therefore it
is more commonly incorporated with other synthetic biodegradable poly-
mers.
In order to create a hybrid scaffold, gelatin was grafted onto electros-
pun PCL nanofibers, then ECs were seeded on the scaffold for cell prolif-
eration studies [58]. First, PCL nanofibers were treated with the air plasma
to introduce-COOH groups on the surface of the fibers, then gelatin mol-
ecule grafting was done. One of the reasons to apply gelatin grafting is to
make the PCL fiber surface more hydrophilic, so the cell can attached eas-
ily [58]. The grafting of gelatin significantly improved the ECs cell attach-
ment and the growth compared to only PCL fibers [58]. The same group
had also tried to electrospun the gelatin fibers and also coelectrospun with
50:50 w/v solution of PCL [17]. The mechanical data (Table 2.2) evalu-
ation showed that gelatin/PCL fibers have less tensile strength compared
to PCL fibers, however, the elongation and deformation properties were
drastically improved [17].
Synthetic polymers such as PCL have a disadvantage because they lack
cell-binding sites unlike natural polymers. Therefore, combining the syn-
thetic polymer with natural polymers (ECM proteins) will significantly
improve the cell adhesion characteristic of the scaffold. One of the ways
to incorporate natural polymer with the synthetic polymer is grafting. Pre-
viously, researchers have used grafting technique to attach the gelatin to
the electrospun fibers. However, there are limitations associated with this
technique, for instance, glutaraldehyde, a cross-linking agent, can greatly
reduce the pore size of the scaffold and can be cytotoxic [59]. Therefore,
scientists preferred to coelectrospun the gelatin and other synthetic bio-
degradable polymer. A comparative study using cospun collagen/gelatin/
PCL scaffold and gelatin/PCL scaffold [60] showed that the average fiber
diameter was increased with the increasing amount of PCL in the PCL/
gelatin composition. In contrast to the fiber size, the pore size decreased
with the increasing synthetic polymer concentration. The combination of
10% PCL with 10% gelatin has significantly improved the mechanical ten-
sile strength compare to PCL/collagen or PCL/elastin.
PLCL electrospun fibers are usually very elastic and soft. On the other
hand, pure gelatin electrospun fibers exhibited hard and brittle behavior.
Therefore, a combination of the PLCL and gelatin solution can provide
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