Biomedical Engineering Reference
In-Depth Information
(nanorough and conventional Ti). This could be a result of the
antibacterial effects caused by the presence of luorine, as shown by
other studies [48, 111, 151]. Additionally, there was also a difference
in the crystallinity between the anodized Ti surfaces, nanorough,
and conventional Ti that can be linked to bacteria adherence.
Nanotextured and nanotubular Ti contained amorphous TiO
2
while
the nanorough and conventional surfaces contained crystalline TiO
2
(anatase and rutile phase). Research has shown that amorphous TiO
2
promoted bacteria attachment compared to anatase TiO
2
(which is
known to possess antibacterial properties) [30,150].
Formation of porous TiO
x
layers on Ti during electrochemical
etching in H
3
PO
4
, CH
3
COOH electrolytes modiied by HF and NH
4
F
was described [50, 51]. The anodization resulted in porous TiO
x
formation, useful in tissue growth and bone bonding. The pore
dimensions increased due to the increase of HF or NH
4
F content in
H
3
PO
4
electrolyte. During anodization at 10 V for 30 min, when the
HF content increased from 0.5 to 10%, the pore diameter increased
from 30 nm up to 8 μm, respectively. Anodization in CH
3
COOH
electrolyte resulted in non-uniform etching with lat hexagonal
islands with nanopores inside surrounded by micropores.
The biocompatibility of the porous surface was investigated
after one and ive days on osteoblasts culture (Fig. 12.5). After the
irst day, we have observed relatively large amount of short ilopodia
(a,b). After 5 days, the cells showed adhesion and proliferation (c,d)
and the osteoblasts covered most of the surface. On the porous
sample, after one day, the cells strongly ixed to the insert, growing
inside the pores. The ability of adhesion and growth on porous
material is a speciic feature of the osteoblasts.
Figure 12.5
Human osteoblasts after 1st (a) and 5th (b) day of the
culture on sample etched at 10 V/30 min in 1M H
3
PO
4
+ 10% HF electrolyte [51].
