Biomedical Engineering Reference
In-Depth Information
mirror-polished and nanostructured surfaces had higher surface
roughness than that of the plastic culture. The cell plastic culture and
the smooth stainless steel discs presented an intermediate surface
energy. The most hydrophobic material was the nanostructured
stainless steel discs.
The surface composition of mirror-polished and nanostructured
stainless steel surfaces was determined by X-ray photoelectron
spectroscopy (Table 12.3). The stainless steel was covered by an
oxide layer composed of iron and chromium oxides (Fe
2
O
3
, Cr
2
O
3
).
The chromium content was higher on Nano-SS as compared with
Smooth-SS while it was the opposite for iron. It may be due to a more
rapid dissolution of iron during anodization. A higher concentration
of carbon and a lower concentration of oxygen were observed on the
nanostructured stainless steel discs as compared with the smooth
stainless steel. This high carbon content on the Nano-SS in the iron
oxide layer may be explained by the anodization process that was
conducted in an organic solvent.
Table 12.3
Surface analyses determined by X-ray photoelectron
spectroscopy of mirror-polished (Smooth-SS) and nano-
structured stainless steel (Nano-SS) [77]
Element (atomic %)
Smooth-SS
Nano-SS
C
37.3 ± 0.7
53.6 ± 1.1
O
52.6 ± 1.0
40.6 ± 0.8
Cr
3.3 ± 0.7
3.6 ± 0.7
Fe
6.7 ± 0.1
2.2 ± 0.1
By comparing cell morphology on the two surfaces at high
magniication, the osteoblastic cells exhibited a round shape on
Smooth-SS while they appeared to have a “star-like” shape with
more cytoplasmic extensions and ilipodia on the Nano-SS after
4 h. The number of branched cells was relatively higher than the
number of round cells on the Nano-SS as compared with Smooth-SS.
Therefore, osteoblastic cells seemed to spread more rapidly on the
nanostructured than on the smooth surface.
Cell proliferation of mouse pre-osteoblasts MC3T3-E1 was
measured through their mitochondrial (MTS) activity at different
time points on to the different substrates and controls. Compared
with plastic culture, MTS cell viability was similar on Smooth-SS
and Nano-SS at 8 days. At day 15, osteoblastic cells proliferated
