wettability may play a major role in adsorption of proteins onto
the surface, as well as in cell adhesion. Cell adhesion is generally
better on hydrophilic surfaces. It is known that changes in the
physicochemical properties, which influence the hydrophilicity of
Ti dioxide, will modulate protein adsorption and further cell
attachment [23]. The degree of hydrophilicity can be estimated
by measuring the contact angle of water droplet on the TiO2 film
as described in previous reports [17]. Calcium and phosphate ions
that have been known to help in bonding the implant to the bone
can be incorporated in the oxide layer during the anodization, and
the topography can be varied by regulating the electrolytes and
electrochemical conditions [24]. According to Maxian et al. [25]
and Cheung et al. [26], the presence of Ca ions has been reported
to be advantageous to cell growth, and in vivo data show that
the implant surfaces containing both Ca and P demonstrate enhanced
bone apposition [27]. Alteration of surface roughness
should also be discussed in association with surface modifications.
Using different surface modifications, a substantial improvement
in implant performance has been demonstrated, and it is related
to surface roughness and chemical composition of the oxide
surface.
In this paper, we report the synthesis of nanoporous titania
with variable chemical compositions and surface characteristics
by anodic oxidation with the application of different ultrasonic
wave powers to the electrolyte containing aqueous calcium acetate
and calcium glycerophosphate. Sonication has been employed as
the energy source for enhancing the rate of chemical reactions that
uniformly transfer the mass throughout the process. The formation
of nanopores using conventional magnetic stirring is retarded due
to the formation of a double layer and diffusion-limited transport
of the species. This research aims to investigate the influence of
ultrasonic irradiation power on the structure and chemical composition
of the anodized surface.