Biomedical Engineering Reference
In-Depth Information
decreased from 167 to 24 nm, osteoblast adhesion got increased
by 51% and ibroblast adhesion responsible for encapsulation was
reduced by 235%.
The difference in the cell density between the conventional and
nanomaterials is given in Table 12.1. It may be noted that, though
different types of cells were utilized for cell culture studies on the
alloys and ceramics, the cell density was observed to be relatively
higher for the nanomaterials when compared to conventional
counterparts.
Table 12.1
Cell density on nano-size (nanophase materials) and micron
size (conventional materials) grains [43]
Increase in surface
area when compared to
conventional materials
Cell density
a
(cells/sq.cm.)
Roughness
(nm)
Material
2000
b
Ti (nano)
15%
11.9
1600
b
Ti-6Al-4V (nano)
23%
15.2
Co-Cr-Mo (nano)
11%
35.6
1450
b
Ti (conventional)
1400
b
Ti-6Al-4V (conventional)
950
b
Co-Cr-Mo (conventional)
600
b
6000
c
Alumina (24 nm) (nano)
8000
c
Titania (39 nm) (nano)
9500
c
Hydroxyapatite (67 nm),
(nano)
5000
c
Alumina (167 nm)
(conventional)
7000
c
Titania (4520 nm)
(conventional)
7000
c
Hydroxyapatite (179 nm)
(conventional)
a
Rounded values;
b
After 3 h;
c
After 5 days
Apart from the roughness, the pore size on the surface also has
an inluence on the protein adhesion. The protein, victronectin,
is generally adsorbed on pores of smaller sizes (0.69, 0.95, and
0.66 nm of Al
2
O
3
, TiO
2
, and HA), on the other hand, the protein
that decreases cell adhesion such as laminin, generally adsorbs to
pore size 2.54, 2.33, and 3.1 μm corresponding to Al
2
O
3
, TiO
2
, and HA
bioceramics [13]. Increased osteoblast adhesion was also observed
on nano HA coated Ti-13Nb-11Zr alloy and further bone ingrowth
toward implant was noted indicating ceramic surface coatings
leading to high osseointegration [20].
