Biomedical Engineering Reference
In-Depth Information
CTS/brushite composite in
a dendritic-like structure
Theoretical approach
of the composite formation
CTS chain in a extended
random coil conformation
Brushite crystallites dispersed
in the CTS matrix
Mineralization
of CTS matrix,
in the first stage
by brushite
(2)
(3)
In alkaline media
brushite is
transformed in HAp
Dendritic core
Raising the pH
toward neutral
range
Parallel orientated
chains domain
(1)
Void space filled
with water
(4)
CTS chain in a worm-like
conformation
HAp in a cluster-like crystallite
size domain
HAp in a scattered-like
crystallite size domain
Figure 4.15
Main stages in the formation of the chitosan/HAp (CTS/HAp) composite structure. (From Rusu, V. M. et al.
2005. Biomaterials 26: 5414-5426. With permission.)
The resorbability of nano-HAp can be increased by the addition of chitosan. Possible
reasons for this are the following: first, the presence of chitosan macromolecules can fur-
ther stimulate the release of calcium ions from the composite matrix; second, the low crys-
tallinity also improves the resorbability [190]. Mineralization of the alginate-chitosan
core-shell capsules is used for the encapsulation and release of a range of human cell types
(e.g., human bone marrow cells, articular cartilage progenitor cells, and adipocytes) and
GF (e.g., recombinant human morphogenetic protein-2 (rh-BMP-2)). The factor can be deliv-
ered to mouse C1C12 promyoblast cells [191].
4.4.2.2 Mineralization through Surface Coating
The apatite coating on chitosan/gelatin films can be formed via the biomimetic process
in SBF or Ca/P buffer solution. The properties of apatite coating could be controlled by
(1) charged density of chitosan-gelatin network films; (2) intensities of interactions among
Search WWH ::




Custom Search