Zilm Michael, Thomson Seamus D, Wei Mei
Department of Materials Science and Engineering, University of Connecticut, 97 North Eagleville Rd, Unit 3136, Storrs, CT 06269, USA.
Department of Aerospace, Mechanical and Mechatronic Engineering, J07 University of Sydney, University of Sydney, Sydney, NSW 2006, Australia.
Materials (Basel). 2015 Sep 18;8(9):6419-6436. doi: 10.3390/ma8095308.
Hydroxyapatite (HA) is a widely studied biomaterial for its similar chemical composition to bone and its osteoconductive properties. The crystal structure of HA is flexible, allowing for a wide range of substitutions which can alter bioactivity, biodegradation, and mechanical properties of the substituted apatite. The thermal stability of a substituted apatite is an indication of its biodegradation . In this study, we investigated the thermal stability and mechanical properties of manganese-substituted hydroxyapatite (MnHA) as it is reported that manganese can enhance cell attachment compared to pure HA. Pure HA and MnHA pellets were sintered over the following temperature ranges: 900 to 1300 °C and 700 to 1300 °C respectively. The sintered pellets were characterized via density measurements, mechanical testing, X-ray diffraction, and field emission electron microscopy. It was found that MnHA was less stable than HA decomposing around 800 °C compared to 1200 °C for HA. The flexural strength of MnHA was weaker than HA due to the decomposition of MnHA at a significantly lower temperature of 800 °C compared to 1100 °C for HA. The low thermal stability of MnHA suggests that a faster dissolution rate compared to pure HA is expected.
羟基磷灰石（HA）因其与骨骼相似的化学成分及其骨传导特性而成为一种被广泛研究的生物材料。HA的晶体结构具有灵活性，允许进行多种取代，这些取代可以改变取代磷灰石的生物活性、生物降解性和机械性能。取代磷灰石的热稳定性是其生物降解性的一个指标。在本研究中，我们研究了锰取代羟基磷灰石（MnHA）的热稳定性和机械性能，因为据报道，与纯HA相比，锰可以增强细胞附着。纯HA和MnHA颗粒分别在以下温度范围内烧结：900至1300°C和700至1300°C。通过密度测量、机械测试、X射线衍射和场发射电子显微镜对烧结颗粒进行了表征。结果发现，MnHA的稳定性低于HA，HA在1200°C左右分解，而MnHA在800°C左右分解。MnHA的弯曲强度比HA弱，因为MnHA在800°C的显著较低温度下分解，而HA在1100°C分解。MnHA的低热稳定性表明，与纯HA相比，其溶解速度预计更快。
