Volume 85, Issue 3 p. 517-522

Biomimetic Hydroxyapatite Coating on Metal Implants

Pamela Habibovic

Pamela Habibovic

IsoTis NV, Professor Bronkhorstlaan 10, 3720 MB Bilthoven, The Netherlands

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Florence Barrère

Florence Barrère

IsoTis NV, Professor Bronkhorstlaan 10, 3720 MB Bilthoven, The Netherlands

iBME, Twente University, The Netherlands

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Clemens A. Van Blitterswijk

Clemens A. Van Blitterswijk

IsoTis NV, Professor Bronkhorstlaan 10, 3720 MB Bilthoven, The Netherlands

iBME, Twente University, The Netherlands

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Klaas de Groot

Klaas de Groot

IsoTis NV, Professor Bronkhorstlaan 10, 3720 MB Bilthoven, The Netherlands

Biomaterial Research Group, Leiden University, The Netherlands

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Pierre Layrolle

Corresponding Author

Pierre Layrolle

IsoTis NV, Professor Bronkhorstlaan 10, 3720 MB Bilthoven, The Netherlands

Member, American Ceramic Society.

Author to whom correspondence should be addressed (E-mail address: [email protected]).Search for more papers by this author
First published: 20 December 2004
Citations: 426

N. P. Padture—contributing editor

Abstract

The combination of the high mechanical strength of metals with the osteoconductive properties of calcium phosphates make hydroxyapatite coatings on titanium implants widely used in orthopedic surgery. However, the most popular coating method, plasma spraying, exhibits some important drawbacks: the inability to cover porous implants and to incorporate biologically active agents, delamination, and particle release. The aim of this study was to elaborate a dense, strong, and thick calcium-phosphate coating on titanium and porous-tantalum implants using a two-step biomimetic procedure. In the first step, the implants were soaked in a solution that was 5 times more concentrated than regular simulated body fluid (SBF-A solution). A thin but uniform amorphous calcium-phosphate coating was deposited on the metal. Then, the implants were immersed in the SBF-B solution, which had a similar composition as the SBF-A solution, but with decreased contents of crystal growth inhibitors (i.e., Mg2+ and HCO3). This resulted in the fast precipitation of a 30 μm thick crystalline calcium-phosphate coating. The pH of the SBF-B solution and the thickness of the crystalline coating layer were studied as a function of time. The Fourier transform infrared spectra and X-ray diffraction patterns showed that this new coating closely resembles bone mineral. Our biomimetic coating should facilitate rapid bone formation around the implant, reducing therewith the patient's recovery time after surgery.