Carbon Nanotubes in Acrylic Bone Cement - Biologically Responsive Biomaterials for Tissue Engineering - page 185

It is clear that the incorporation of CNT offers significant potential to improve
the properties for many existing materials; the challenge remains for the superior
properties exhibited by CNT individually to be successfully applied and optimised
in practical applications such as nanocomposites. Not only do the properties of the
CNT themselves vary due to impurities during processing [ 7 ], but on addition of
CNT to a matrix material, the problem becomes multifaceted: CNT dimensions,
dispersion, alignment, concentration, CNT-matrix interface/adhesion and choice of
matrix are some of the many issues that govern the final properties of the composite
material. At present, production of high-purity SWCNT still remains costly and of
a low yield: purification reduces yield further, adds to cost and damages the struc-
ture [ 3 ]. Low manufacturing costs and high yields of aligned MWCNTs are now
possible however, making them the preferred choice in bulk composite material
development.

8.3.6 CNT-Reinforced Biomaterials

Nanotechnology in biomaterials is not a new idea [ 36 ] . Nanomaterials have been
used as implant coatings, bulk materials, in drug delivery, actuators, diagnostic tools
and devices [ 87 ]. When biomaterials incorporating nanomaterials are studied, much
of the emphasis is on the interaction between the biological tissue and the biomate-
rial at a molecular level. Using the interface between bone, and a metallic implant
as an example, a positive biological interaction is essential if a good fixation is to be
obtained. Chun et al. [ 15 ] examined this interaction by coating titanium (Ti) sub-
strates with helical rosette self-assembled organic nanotubes (HRN). HRNs display
chemical and structural similarities to various constituents of bone (Fig. 8.8 ). Chun
et al. [ 15 ] found that the HRN-coated titanium displayed enhanced interaction with
the naturally occurring nanostructures' constituents such as collagen fibres and

Fig. 8.8 Diagram of helical
rosette nanotube (HRN) [ 15 ]