Interaction ofCartilage andCeramic Matrix - Tissue Engineering: Cell-Surface Interactions for Tissue Culture - page 307

with carrier w/o carrier with carrier w/o carrier

0.8 30

25

0.6

20

0.4 15

10

0.2

5

0.0 0

5 0 5 0 5 0 5 0

5 0 5 0 5 0 5 0

Time [d] Time[d]

w ith c arrier w /o c arri e r

200

150

100

50

0

5 0 5 0 5 0 5 0

Time [d]

Fig. 6 DNA content, GAG content and GAG-to-DNA ratio of cartilage-carrier constructs and
cartilage grown without a carrier cultivated for 5 weeks. Significant differences (a \0.05) are not
shown (n = 4-5)

Differences in the development of cartilage-carrier constructs and unsupported
cartilage can be already observed after 7 days of cultivation. In particularly, mass,
Young's modulus, GAG content and GAG-to-DNA ratio developed differently
depending on culture conditions. While a decrease in Young's modulus and GAG
content of cartilage cultivated without a carrier appeared after 3 weeks, the same
but less pronounced effect could be observed for cartilage-carrier constructs after
only 2 weeks. While the total GAG content of unsupported cartilage was increased
by a factor of 4.5, the GAG content of cartilage-carrier constructs only doubled
within 5 weeks (Table 1 ). Thus, exogenous stimulation of cells must be applied
already after 2 weeks during cultivation of cartilage without a carrier, while cul-
tivation of cartilage-carrier constructs must be optimized after 3 weeks.

5 Impact of Surface Structure

As many studies have already shown, the surface structure of biomaterials con-
siderably influences cell behaviour and with it the success of tissue engineering
methods. For example, Hallab et al. [ 28 ] measured enhanced adhesion shear