Biomedical Engineering Reference
In-Depth Information
which are required in most cases when used as scaffold in tissue engineer-
ing. Compared with animal derived polymers, BC is free of any occur-
rence of cross-infection that can be associated with collagen. The authors
found that there are different interactions between unphosphorylated and
phosphorylated BC fi bers and HAp. It was found that phosphorylated BC
could act as potential substrate for apatite nucleation. The observed 3D
porous network structure and interconnected pores, whose parameters
can be adjusted over a wide range, make the BC/HAp composites prom-
ising materials in tissue engineering. In addition, it is expected that the
advantageous mechanical properties of BC will allow the design of a wide
range of BC/HAp composites with mechanical properties ranging from
those analogous to soft tissues to those similar to hard tissues, by control-
ling the ratio of HAp to BC and their 3D structure.
Jiang and coworkers [112] developed a new type of bone-replac-
ing material composed of different weight ratios of nanoHAp and a
CS-carboxymethylcellulose network. NanoHAp was uniformly dispersed
in the composite in the form of nanometer-grade short crystals, which
ensured that the composite had high compressive strength. For the com-
posite with 40 wt% NanoHAp, the compressive strength reached nearly
120 MPa, which can meet the requirement of initial mechanical properties
for bone repair material. Moreover, its weight loss was up to 56.44% after
soaking in SBF for 8 weeks, which indicates a degradable composite. Next,
apatite particles aggregated to form a bioactive apatite layer deposited on
the surface.
5.5
Conclusions and Future Remarks
Therapeutic repair of damaged bone tissue and its regeneration engi-
neering protocols have generated signifi cant interest in the scientifi c and
medical communities research, and developments in these fi elds, particu-
larly in preclinical animal models and in clinical pilot studies have, so far,
been very promising. Recent progress in the design and incorporation of
bionanomaterials into the biocompatible polymer matrices, and process-
ing technologies able to produce porous structure with high porosity with
tailored mechanical and biological properties, provided some unique pro-
tocols for the development of polymer nanocomposites scaffolds. Recent
studies indicate that designing scaffolds construct with the combination of
ceramic nanoparticles (e.g., HAp, TCP) into the polymer matrix, have great
potential for optimal bone tissue regeneration. In particular, biodegradable
polymer-nanoHAp composites display controllable bioresorption kinet-
ics and the suffi cient mechanical strength needed for applications in bone
tissue engineering. The high surface area nanostructured HAp allows the
interactions with the lowest hierarchical levels of bone structure, although
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