Biomedical Engineering Reference
In-Depth Information
1.2
60
0.6
50
0.10
20
0.05
10
*
0.00
0
construct
w/o
with
carrier
native
construct
w/o
with
native
carrier
carrier
carrier
Fig. 3 Young's modulus and glycosaminoglycan (GAG) content of cartilage-carrier constructs
(construct), cartilage without a carrier (w/o carrier) and cartilage (with carrier) cultivated in
media containing a carrier (n = 4-5, a \ 0.05)
Fig. 4 Histological sections stained with Safranin O of a cartilage-carrier constructs, b cartilage
without a carrier and c cartilage cultivated in media containing a carrier
To measure the absolute values, native porcine cartilage from which chondrocytes
were isolated was investigated with the same analytical methods and is addi-
tionally illustrated in Fig.
3
. While the Young's modulus for unsupported cartilage
was only about 13% of native cartilage, the GAG content reached 43%.
To estimate tissue organization, histological sections of the in vitro generated
cartilage tissue were prepared and glycosaminoglycans as cartilage extracellular
matrix components were stained red with Safranin O as shown in Fig.
4
. While the
tissue of cartilage-carrier constructs showed areas with low glycosaminoglycan
content, the histological sections of cartilage without using a carrier during
cultivation showed a homogenous tissue in which glycosaminoglycans and
chondrocytes were evenly distributed. Additionally, a more prominent staining for
collagen type II than type I could be observed under all conditions (not shown
here). The distribution of collagens is comparable to that seen with Safranin
O staining. Histological slide in Fig.
4
(a) shows that the different measured values
of the GAG content (and with it possibly also of the increased Young's modulus)
of cartilage-carrier constructs compared to unsupported cartilage arose not only
from the tissue formed at the interface between biomaterial and cartilage, but from
the entire engineered tissue.
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