Biomedical Engineering Reference
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70 nm in diameter, which consisted of spherical polymer nano-sized
particles enclosed within a continuous 10-20 nm thick surface layer
of ACP [475]. Synthesis of hollow spherical calcium orthophosphate
nano-sized particles using polymeric templates has been also
reported by other researchers [476]. Furthermore, bundles of
surfactant-coated ACP nanodimensional filaments of ~2 nm in width
and >300 μm in length were synthesized in reverse micelles [477].
Bundles of the nanodimensional filaments were stable in the reverse
micelle phase up to around 5 days, after which they transformed
into 5 nm-wide surfactant-coated CDHA rods. Discrete filaments of
100-500 × 10-15 nm in size and a linear superstructure based on
the side-on stacking of surfactant-coated ACP nano-sized rods were
also prepared [417]. A double reverse-micelle strategy was realized
to synthesize amine, carboxylate-, and polyethylene glycol surface
functionalized calcium orthophosphate nano-sized particles of an
undisclosed nature [478]. Furthermore, the reverse micelle technique
might be applied to prepare nanodimensional DCPA [428, 479].
Concerning OCP, an oriented growth of nanodimensional belts
of OCP with a clean surface has been achieved by wet-chemical
approach using cetyltrimethylammonium bromide [480]. Pulsed
laser deposition technique was employed to obtain thin films of
nanocrystalline OCP on pure Ti substrates [481]. The deposition was
performed by a pulsed UV laser source in a flux of hot water vapors.
High-resolution electron microscopy and X-ray diffraction at grazing
incidence investigations indicated that the coatings were made
of nanocrystalline OCP (unfortunately, the dimensions were not
indicated).
tests proved that both fibroblasts and osteoblasts
adhered, reached a normal morphology, proliferated and remained
viable when cultured on the nanocrystalline OCP coatings, supporting
a good biocompatibility and absence of any toxicity [481].
Nanodimensional powders of BCP (both HA + β-TCP [482, 483]
and HA + α-TCP [484]) have been fabricated as well. To get the details,
the interested readers are referred to the original publications.
Similar to that for apatites (see above), the surface of nano-sized
particles of both TCP and other calcium orthophosphate might be
functionalized by various compounds to provide new important
properties [171, 478, 484-489], such as fluorescence [487, 488]
or a good disperseability in organic solvents [484]. Furthermore,
nano-sized calcium orthophosphates might be used as templates to
manufacture nanodimensional capsules [490].
In vitro
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