Biomedical Engineering Reference
In-Depth Information
more rapidly on both smooth and nanostructured stainless steel sub-
strates than on culture plastic.
The differentiation of osteoblastic cells was assessed using ALP
(Alkaline phosphatase) activity normalized to protein content after
culturing MC3T3-E1 on the different substrates for 8, 15, and 21 days.
The differentiation increased with culture time on both Smooth-SS
and Nano-SS substrates. ALP activity was better enhanced at 21 days
on the nanostructured surface than on the Smooth-SS.
A positive inluence for nanotopography on stainless steel
with regard to the spreading of osteoblastic cells was observed
[77]. Analysis of osteoblast morphology revealed that there were
extensive interactions between osteoblasts and nanoscale features
as they extended ilipodia to a greater extent on Nano-SS than on
Smooth-SS. Webster and Ejiofor [142] have reported that osteoblasts
extended their ilipodia and interacted with nanostructured surfaces
faster than those on control surfaces.
The surface topography of bio-implant materials dramatically
inluences their cell response. Recently, a set of unique structures
ranging from mesoporous nanoscaffolds, nanolowers, nanoneedles,
nanorods, and octahedral bipyramids were fabricated by
systematically tuning the hydrothermal conditions such as reaction
medium composition, concentration, temperature, and time duration
[32]. The cytotoxicity of surface modiied Ti was assessed using
human primary osteoblastic cells, and more than 90% of the cells
were found to be viable after 24 h of incubation. Protein adsorption
studies revealed that the surface modiied nanostructures on
titanium adsorbed more proteins, suggesting that they are capable
of promoting cell adhesion/attachment.
Recently, a monoclinic zirconia coating with a nanostructural
surface was prepared on the Ti-6Al-4V substrate by an atmospheric
plasma-spraying technique, and its microstructure and composition,
as well as mechanical and biological properties, were investigated to
explore potential application as a bioactive coating on bone implants
[130]. X-ray diffraction, transmission electron microscopy, scanning
electron microscopy, and Raman spectroscopy revealed that the
zirconia coating was composed of monoclinic zirconia which was
stable at low temperature, and its surface consists of nano-size
grains 30-50nm in size. The bond strength between the coating and
the Ti-6Al-4V substrate was 48.4±6.1MPa, which is higher than
that of plasma-sprayed HA coatings.
