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I '
-Grau de sigilo:
-Titulo: Bioactivity Improvement of Porous Titanium Samples
via Biomimetic Method
I OConfidencial
I-Data de Emlssao.
I_N° de copias:
W. S. Medeiros, M. C. Andrade, L. C. Pereira, M. V. Oliveira, C. A. A. Cairo.
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Bioactivity improvement
Me 3985
Bioactivity Improvement of Porous Titanium Samples via Biomimetic Method
Federal do Rio de Janeiro - UFRJ/PEMM/COPPE,
CT/Bloco F/saia 210, Ilha do
Fundao - Cidade Universitaria,
Rio de Janeiro, [email protected]
2lnstituto Nacional de Tecnologia
Av. Venezuela
nO 821602, Sallde,
Rio de Janeiro, 2008]-3 ]2, [email protected]
3Centro Tecnico Aeroespacial
- Instituto de Aeronautica
e Espa<;o - CT A/IAEI AMR
4Centro de Tecnologia
Abstract - Porous titanium substrates were submitted to the biomimetic process in ordcr to improve its
osteoconductivity. The samples were chcmically treated. hcat treated at 400 DCand 600 DCand soaked into a modified
body fluid solution during periods from 2 to 28 days. Calcium phosphates were found on all samples.
Titanium is known to be chemically stable in the human body. Porous titanium implants have been used in order
to improve the interfacial resistance between the material and bone, providing a more efficient fixation of the implant.
The bioactivation
of this porous structure can be achieved through chemical and thermal pre-treatments I. The
biomimetic process is employed both to evaluate the material biocompatibility
and to obtain calcium phosphate coatings
on metallic substrates. This process is based on the nucleation and growth of calcium phosphate films on a substrate
immersed in body tluid solution (SBF) at 37°C. When it is associated with chemical and thermal pre-treatments
of the
substrate. the chemical adhesion of the calcium phosphate film increases2-J.
The biomimetic
approach presents
advantages such as: the low temperature of the process. which is usable to any heat sensitive material. formation of
bonelike apatite crystals with high bioactivity, deposition on and into porous surfaces and the possibility of bone growth
stimulating factors incorporation4.
The aim of this work is to apply the biomimetic process which has been widely used on smooth surface on a
porous titanium substrate produced by powder metallurgy (figure I) in order to improve its osteoconductivit/.
titanium samples with about 63% of porosity were treated with a 1M NaOH solution at 130°C in an autoclave in order
to form a sodium titanate hydrogel layer on the surface. The samples were heat treated at 400 °C and 600 DC for
dehydration and stabilization of the titanate layer. The porous titanium substrates were submitted to modified body tluid
solution (mSBF)-for 2, 7, 14 and 28 days to evaluate the evolution of calcium phosphate phase precipitation.
The formation of a needlelike phase (figure 2) was observed after pre-treatments
which is expected to be sodium
titanate. After mSBF immersion. a phase rich with Ca and P was detected in the EDS expectrum of the sample soaked
for just 2 days and also in other samples (7, 14,28 days). The sample soaked for 28 days exhibited a calcium phosphate
coating morphology on the surface, showing the good potential of this process for coating this material. This research is
currently in progress. and the next step will be the evaluation of the nature and morphology of the calcium phosphate
tilm deposited on the porous titanium.
Fig. I. Porous Ti micrograph of a sample with
about 63% of porosity without pre-treatments.
fig. 2. Porous Ti micrograph of a sample with
chemical and thermal pre-treatments showing
needles on the surlace.
[I] H.Q. Nguyen, DA Deporter, R.M. Pilliar, N. Valiquette, R. Yakubovitch, Biomaterials 865-876, 25 (20041.
[2] M. C. de Andrade, M. R. T. filgueiras and T. Ogasawara, J. Euro. ('eram. Soc. 505-510,22 (2002).
131 S fujibayashi. N. Masashi, H. M. Kim, T Kokubo, T. Nakamura, Biomalerials 443-450, 25 (2004).
141 P l1abibovie, f. Barrere, C. A. Van Blitterswijk, K. de Groot and P Layrolle, J. Am ('eram. Soc. 517-522. 85[3J (2002).

Bioactivity improvement of porous titanium samples