Biomedical Engineering Reference
In-Depth Information
interfacial bonding with other components of the composites.
Furthermore, functionalization of carbon nanotubes with carboxylic
groups was found to confer a capacity to induce calcification similar
to woven bones [223]. Interestingly, but carbon nanotubes might be
functionalized by
in situ
deposition of CDHA on their surface [224].
6.4
Calcium Orthophosphate-Based
Biocomposites and Hybrid Biomaterials
Generally, the use of calcium orthophosphate-based biocomposites
and hybrid biomaterials for clinical applications includes several
(partly overlapping) broad areas:
• biocomposites with polymers,
• cement-based biocomposites and concretes,
• biocomposites based on nanodimensional calcium
orthophosphates and nanodimensional biocomposites,
• biocomposites with collagen,
• biocomposites with other bioorganic compounds and/or
biological macromolecules,
• injectable bone substitutes (IBS),
• biocomposites with glasses, inorganic compounds, carbon
and metals,
• functionally graded biocomposites,
• biosensors.
The details on each subject are given below.
6.4.1
Biocomposites with Polymers
Typically, the polymeric components of biocomposites and hybrid
biomaterials comprise polymers that both have shown a good
biocompatibility and are routinely used in surgical applications. In
general, since polymers have a low modulus (2-7 GPa, as the maximum)
as compared to that of bone (3-30 GPa), calcium orthophosphate
bioceramics need to be loaded at a high weight% ratio. Besides,
general knowledge on composite mechanics suggests that any high
aspect ratio particles, such as whiskers or fibers, significantly improve
the modulus at a lower loading [179]. Thus, some attempts have been
already performed to prepare biocomposites containing whisker-
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