Synthesis and characterization of lanthanum-incorporated hydroxyapatite coatings / 中国组织工程研究

ABSTRACT

BACKGROUND:Hydroxyapatite-coated titanium substrates improve the biocompatibility and have the property of intimating ossteointegration with host bonebed. However, hydroxyapatite lacks the necessary mechanical strength and degrades easily in the extracelular fluids, which may affect the stability of the titanium implant. OBJECTIVE:To study the synthesis and characterization of lanthanum-incorporated hydroxyapatite coatings. METHODS: Lanthanum-incorporated hydroxyapatite coatings were prepared by hydroxyapatite and 10%, 20% and 30% lanthanum, respectively, by means of sol-gel, which were then deposited on titanium substrates with dip-withdrawal technique. Surface morphology and crystaline microstructure of the coatings were observed by scanning electron microscope. The presence of functional groups for the obtained samples was performed by Fourier transform infrared absorption spectroscopy and X-ray diffraction. The Ca2+ concentration released from the coatings was measured by atomic absorption spectrometry for analysis of degradation property. RESULTS AND CONCLUSION: With the increase of lanthanum content, the diffraction peak and crystalinity of lanthanum-incorporated hydroxyapatite coatings were increased, but the whole structure of lanthanum-incorporated hydroxyapatites had little changes. The crystal structure maintained stable with charge balance. The lanthanum-incorporated hydroxyapatite coatings showed uniform and high-dense structure and were free of cracks, indicating the coatings had good bonding strength. Under the simulated biological environment, based on the determination of Ca2+ release from the coatings, we can conclude the lanthanum-incorporated hydroxyapatite coatings have a stronger acidoresistance.