Biomedical Engineering Reference
In-Depth Information
4a.2.2 Gelatin
Gelatin is synthesized by the partial dissociation of the trimeric
structure of collagen and maintains the bioactive properties of
collagen [18]. Chemically unmodified gelatin is difficult to utilize as
a culture scaffold; in particular gelatin gels are dynamically weak
and cannot be utilized as a three-dimensional (3D) culture scaffold
[19]. During biological test using cardiomyocytes in neonatal rats,
it was shown that gelatin hydrogel was biocompatible and retained
the capacity for cell survival and cell adhesion [20]. It was reported
that succinylated gelatin hydrogel could control the release of
chemokines and stromal cell-derived factor 1 (SDF-1) by modifying
the hydrogel preparation conditions. In addition, the efficiency of
angiogenesis following the transplantation of SDF-1-containing
hydrogel was significantly higher compared to the injection of SDF-1
solution [21].
4a.2.3 Fibrin
Fibrin is a fibrillar protein that forms a mesh and is involved in
blood coagulation, platelet activation, and protein polymerization
[22]. Fibrin networks involved in arginine-glycine-aspartic acid
(RGD) motifs are closely related to the cell adhesion and binding
of important growth factors. Fibrin is important in hemostasis and
is produced from fibrinogen by thrombin. One of the advantages
of using fibrin is that fibrinogen can be extracted from autologous
human plasma, thereby suppressing the immunoreaction. Moreover,
fibrin mixed with other gels, such as hyaluronic acid-based gels, has
been applied to chondrocytes in a knee repair model [23]. Fibrin
glue composed of fibrinogen and thrombin solutions has been
used to control bleeding or to adhere tissues after surgery [24] or
to deliver extraneous growth factors to accelerate wound healing
[25] in clinical medicine. The fibrin matrix, as found in fibrin gel and
fibrin glue, is a natural material that can be used as an injectable
scaffold. By transplantation of an injectable fibrin matrix containing
bone marrow mononuclear cells (BMMNCs) into an infarcted
myocardium, the angiogenic effect is enhanced in comparison to the
injection of a solution containing only BMMNCs [26].
