Biomedical Engineering Reference
In-Depth Information
Substantial progress has been made in understanding adhesion process on surfaces after or
while immersed in liquids. In these research a number of developed techniques such as,
X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), ellipsometry, fourier
transform infrared attenuated total reflectance (FTIR/ATR), quartz crystal microbalance
(QCM), surface plasmon resonance (SPR), dual polarization interferometry, total internal
reflectance fluorescence (TIRF), voltammetry and electrochemical impedance spectroscopy
(EIS) have been deployed. When measuring in liquid environment the potential amount of
usable devices rapidly decreases and none of the listed devices are alone able to describe, in
detail, the adsorption process of biomolecules. (Agnihotri & Siedlecki, 2004; Cacciafesta et al.,
2001; Cai et al., 2006; 2005; Höök et al., 2002b; Jackson et al., 2000; Jandt, 2001; Roach et al.,
2005; Roach, Farrar & Perry, 2006; Roach, Shirtcliffe, Farrar & Perry, 2006; Soman et al., 2008;
Sonesson et al., 2007; Swann et al., 2004; Toscano & Santore, 2006; Van De Keere et al., 2008;
Vanderah et al., 2004; Wang et al., 2003; Wertz & Santore, 1999; 2001; 2002; Xu & Siedlecki,
2007)
Adsorption of HPF molecules at the rough bulk titanium and modified titanium surfaces
increases the scattering and decreases the coherence of the probing laser light beam. These
changes in coherence as well as in signal magnitude can be detected with diffractive optical
element (DOE) based sensor. DOE sensor is a non-contact optical method, in detection of
biomolecules, which can sense changes on the measured biosurface as well as changes in the
surface itself. (Silvennoinen, Hason, Vetterl, Penttinen, Silvennoinen, Myller, Cernochova,
Bartakova, Prachar & Cvrcek, 2010; Silvennoinen, Peiponen & Myller, 2008; Silvennoinen,
Vetterl, Hason, Silvennoinen, Myller, Vanek & Cvrcek, 2010; Silvennoinen, Vetterl, Hason,
Tuononen, Silvennoinen, Myller, Cvrcek, Vanek & Prachar, 2008)
HPF protein molecules adsorb stronger on the titanium surface, which is treated by polishing
and etching, than at the surface treated only by polishing due to an increase of surface
area caused by etching and thus increase the interactions caused by van der Waals forces
(Parsegian, 2005; Silvennoinen, Hason, Vetterl, Penttinen, Silvennoinen, Myller, Cernochova,
Bartakova, Prachar & Cvrcek, 2010; Silvennoinen, Vetterl, Hason, Tuononen, Silvennoinen,
Myller, Cvrcek, Vanek & Prachar, 2008). The effective surface tension, as well as the surface
energy related to the topography of surface, is assumed to influence the final interactions of
the implant with the surrounding environment. It is also reported that rough surfaces promote
better osseointegration than smooth surfaces (Brett et al., 2004; Cochran, 1999; Jansson &
Tengvall, 2004; Webster et al., 1999).
Treatment of titanium surface by titanium doped hydrocarbon layer is observed to have
strong influence on the adsorption of HPF molecules. Also HPF adsorption is detected on
the titanium alloy surface as Ti6Al4V. Adsorption of the elongated HPF on a titanium-based
surface is monitored by analyzing permittivity and optical roughness of protein-modified
surfaces by using a DOE sensor and a variable angle spectro-ellipsometry (VASE). The
biological experiment, when cultivation of osteoblast at the titanium surface was performed,
showed that the surface treated by polishing and etching is more proper for the bone cell
growth than the surface treated only by polishing. The best adsorption of fibrinogen was
observed at the titanium doped hydrocarbon surface prepared by plasma-enhanced chemical
vapor deposition, when the optimal ratio was Ti
0.38
C
0.62
and Ti
0.09
C
0.91
.Thesu faceof
dental implants treated by this way should increase their biocompatibility, speed up their
osseointegration and healing. Also, due to low value of Young modulus and relatively easy
forming, even in cold processing, the alloys could be the future material in implantology.
Aging of titanium surface affects to the adsorption behavior of HPF proteins, which may
be caused from the consecutive adsorption of carbon and oxygen from air on the surface
