Stem Cell Differentiation Depending on Different Surfaces - Tissue Engineering: Cell-Surface Interactions for Tissue Culture - page 274

embedding of
bioactive molecules

application of
microspheres

mechanical mixture
of a polymer and a
ceramic component

surface functionalization

Fig. 3 Different fabrication methods for ceramic-based composite biomaterials

ceramics, resulting in a mechanically stable and bioactive matrix. The combination
of these components can be realized by coating a porous ceramic with the modified
polymer. However, the polymer coating can plug the pores of the ceramic and
therefore negatively influence the transportation of nutrients and waste material.
Thus, only biodegradable polymers such as polycaprolactone [ 75 ] or polyvinyl-
pyrrolidone [ 76 ] in combination with highly porous ceramics can be applied.
The release of the bioactive molecules is caused by the degradation of the matrix.
Degradation signifies the cleavage of polymers, due to either an enzymatic or a
hydrolytic process. Hence, the dose and the lifetime depend on the degradation
rate. Finally, the result is a thin layer of bioactive molecules surrounding the
matrix.
Another promising alternative to combine natural and synthetic components is

the application of microspheres. Microspheres are small spherical polymer