Biomedical Engineering Reference
In-Depth Information
From the perspective of surface modification of 3D porous scaf-
folds, the biggest advantage of this hydrothermal process is that
the alkaline solution can reach the entire exposed surface, irrespec-
tive of the complex topography, due to its non-line-of-sight nature.
In contrary, most other reported techniques can only be used to
fabricate nano/micro porous structures on planar samples with
simple topographies.
20
,
31
−
33
Furthermore, this hierarchical scaffold
has no distinct interface between the substrate and the nanos-
tructured layer, which is different from hybrid composites filled
with a layer of organic nano matrix by self-assembly.
34
The nat-
ural growth directly from the substrate strengthens the bonding
between the scaffolds and nanowires/nanobelts, favoring a smooth
junction between bone tissues and scaffolds, benefiting the long-
term fixation of the 3D scaffolds, which can possibly extend the
lifetime of the implants. Our recent contact-angle measurements
indicatethat1Dsurfacenanotitanatescansignificantlyimprovethe
hydrophilicity of both Ti and NiTi scaffolds.
16
On the other hand,
other biodegradable polymer scaffolds, such as poly(
L
-lactic acid)
(PLLA),
19
,
35
poly(
DL
-lactic-
co
-glycolic acid) (PLGA),
35
polystyrene
(PS),
36
and poly(ethylene terephthalate) (PET),
37
have to undergo
surface modification before
in vitro
or
in vivo
tests due to their
hydrophobic nature. In practice, good hydrophilicity can improve
the biocompatibility of biomaterials. Our cell culture tests show
that these surface 1D titanates nanowires/nanobelts significantly
enhance cell adhesion and proliferation (Fig. 3.10).
Figure 3.10.
Microscopic view of cell growth on the surface of microp-
orous NiTi with or without nanostructured titanate. (a) Untreated surface
and (b) surface with nanostructured titanate.
16
See also Color Insert.
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