氧化钛催化羟基磷灰石分解制备可降解磷酸钙陶瓷

本文将纳米锐钛矿型氧化钛(TiO2)作为催化剂添加到羟基磷灰石(HA)中,经烧结制成可降解的磷酸钙陶瓷,采用X射线衍射(XRD),扫描电镜(SEM),体外模拟实验等手段对不同制作工艺的陶瓷进行表征,考察TiO2的添加量和保温时间对磷酸钙陶瓷性能的影响。实验表明,在较低的温度下,TiO2可以降低HA的高温稳定性,使HA分解成磷酸四钙(TTCP)和磷酸三钙(TCP)。由于TCP具有良好的降解性,TiO2的加入极大的提高了HA的降解速率,且随着TiO2添加量的增加降解速率逐渐增大,保温时间越长,降解速率愈小;浸泡SBF结果显示,TiO2的加入可以提高陶瓷沉积活性磷灰石层的能力,但沉积能力与TiO2添加比例不成正比,添加7wt%的材料沉积最快;细胞实验表明,TiO2的加入不影响HA促进细胞增殖分化的能力。使用氧化钛催化分解HA,可能是制备具有良好生物学性能的可降解磷酸钙陶瓷的有效手段。

Degradable Calcium Phosphate Ceramics Prepared by Sintering Hydroxyapatite with TiO2 Catalyst

Titania was employed as a catalyst additive for the preparation of biodegradable hydroxyapatite/titania (HA/TiO₂) composite ceramics in this work. The ceramics were characterized with X-ray diffraction (XRD), scanning electro-microscopy (SEM), and simulated body fluid (SBF) soaking experiments to investigate the effect of TiO₂. The experiment showed that TiO₂ could decrease the thermal stability of HA and make HA decompose into TCP and TTCP at a low temperature. Due to the good degradable ability of TCP, the biodegradable property of HA was improved significantly by addition of TiO₂ and the degradation speed increased with the increase of TiO₂ content. The longer the sintering time, the lower the degradable speed was. The simulated body fluid test showed that the addition of TiO₂ could improve the apatite formation ability. But the deposition property is not increased in proportion to the TiO₂ content, while 7wt% TiO₂ content ceramic exhibited an optimal ratio for inducing apatite nucleation. Cell proliferation results indicated that the biocompatibility of HA were not affected by the addition of TiO₂. It might be a potential method to prepare biodegradable calcium phosphate ceramics with excellent bioactivity by using TiO₂ as catalyst to decompose HA.