Biomedical Engineering Reference
In-Depth Information
9.7 In vivo comparison of unmodified titanium and anodized titanium. (Arrows
point out the comparison of bone growth (top) and inflammatory responses
(bone) between unmodified and anodized titanium. Adapted from Puckett et
al. [47].)
parameters of anodized titanium, like oxide thickness, the pore size distribution,
the porosity and the crystallinity of the surface oxides may be factors that
influence tissue±material interactions. Similar experiments were also conducted
with sheep and rats in which anodized titanium screws or rods were inserted for
4 to 12 weeks. Again, as shown in Fig. 9.7, histological results showed that
anodized nanotubular titanium implants have excellent cytocompatibility
properties and an ability to quickly grow bone next to the implant [48±50].
Moreover, no infection or inflammatory responses were observed around the
anodized nanotubular titanium screws (Fig. 9.7). It is also important to note that
anodization is a quick (less than an hour) and inexpensive technique to modify
the surfaces of titanium-based implants to improve bone cell functions required
for improving orthopedic applications.
As a comparison of all three methods mentioned here for nanostructured
metal modification, wet chemistry etching is the easiest approach. It requires
little equipment and can react with a large amount of metal samples at the same
time. However, the disadvantage of this method is that it is an uncontrollable
process creating uneven surface morphologies. In contrast, the Temescal
electron beam evaporation technique requires a high vacuum chamber and an
extensive energy source supply. In addition, the evaporation and condensation of
metal atoms usually take a little bit longer than chemical etching. However,
Temescal electron beam evaporation can provide even or patterned nano-surface
