Biomedical Engineering Reference
In-Depth Information
using the same synthetic materials with present technologies. This
is because biological organisms produce biocomposites that are
organized in terms of both composition and structure, containing
both brittle calcium orthophosphates and ductile bioorganic
components in very complex structures, hierarchically organized at
the nano-, micro-, and meso-levels. Additionally, the calcified tissues
are always multifunctional: for example, bone provides structural
support for the body plus blood cell formation. The third defining
characteristic of biological systems, in contrast with current synthetic
systems, is their self-healing ability, which is nearly universal in
nature. These complex structures, which have risen from millions of
years of evolution, inspire materials scientists in the design of novel
biomaterials [1172].
Obviously, no single-phase biomaterial is able to provide all
the essential features of bones and/or other calcified tissues and
therefore, there is a great need to engineer multi-phase biomaterials
(biocomposites) with a structure and composition mimicking those
of natural bones. The studies summarized in this review have shown
that the proper combination of a ductile matrix with a brittle, hard,
and bioactive calcium orthophosphate filler offers many advantages
for biomedical applications. Namely, the desirable properties
of some components can compensate for a poor mechanical
behavior of calcium orthophosphate bioceramics, while in turn the
desirable bioactive properties of calcium orthophosphates improve
those of other phases, thus expanding the possible application
of each material within the body [102]. However, the reviewed
literature clearly indicates that among possible types of calcium
orthophosphate-based biocomposites and hybrid biomaterials
only simple, complex and graded ones, as well as fibrous, laminar
and particulate ones (see classification types of the composites in
section
) have been investigated. Presumably, a future progress
in this subject will require concentrating efforts on elaboration
and development of both hierarchical and hybrid biocomposites.
Furthermore, following the modern tendency of tissue engineering,
a novel generation of calcium orthophosphate-based biocomposites
and hybrid biomaterials should also contain a biological living part.
To conclude, the future of the calcium orthophosphate-based
biocomposites and hybrid biomaterials is now directly dependent
on the formation of multidisciplinary teams composed of experts
but primarily experts ready to collaborate in close collaboration
6.2
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