含镁羟基磷灰石的制备与性能研究

Preparation and property of magnesium-substituted hydroxyapatite

自然骨的组成和结晶度均不同于人工合成的羟基磷灰石[Ca10(PO4)6(OH)2,hydroxyapatite,HA],是一种典型的缺钙羟基磷灰石,还含有镁(Mg)、锶(Sr)、钠(Na)、钾(K)、氟(F)等离子。为满足临床要求,常常需要在HA中添加一些元素来改善其性能。含镁羟基磷灰石(Mg-HA)就是其中的一类改性材料。以四水硝酸钙[Ca(NO3)2.4H2O]、磷酸氢二铵[(NH4)2HPO4]、六水硝酸镁[Mg(NO3)2.6H2O]为原料,在180℃下水热处理8h制得Mg-HA。通过XRD、IR、TEM、EDX和TG/DTA对Mg-HA的晶相、化学组成、形貌和热稳定性进行分析,并通过细胞培养,MTT比色法对材料的细胞毒性进行评价。结果表明,Mg取代部分钙(Ca)进入HA的晶格中。随着Mg含量的提高,Mg-HA晶粒尺寸呈减小趋势,热稳定性降低,掺镁对羟基磷灰石细胞毒性影响较小,Mg-HA具有较好的生物相容性。

HA and bone mineral are somewhat different in composition and degree of crystalline.Bone mineral is typically calcium deficient HA and contains carbonate substitutions.Other ions present in bone mineral include magnesium （Mg^2＋）,strontium （Sr^2＋）,sodium （Na^＋）,potassium （K^＋） and fluoride （F^-） ions.To meet the requirements for clinical applications,some elements are substituted into the apatite crystal to improve its function.Magnesium-substituted hydroxyapatite （Mg-HA） is one of these modification materials.Magnesium-substituted HA powders were prepared by the hydrothermal method at 180℃ for 8h using Ca（NO3）2,（NH4）2HPO4 and Mg（NO3）2 as initial reagents.X-ray diffraction,Fourier transform infrared spectroscopy,transmission electron microscope,energy dispersive X-ray,and thermogravimetric-differential thermal analysis were used to characterize the crystalline phase,chemical composition,morphology,and thermal stability of the Mg-HA.And MTT assay was used to detect the cytotoxicity of Mg-HA.The results show that Mg^2＋ ions are incorporated into the HA crystal structure.The crystal grain size of the Mg-HA decreased when the Mg^2＋ content was increased.The apatites thermal stability decreased because of the Mg^2＋ addition.There＇s no apparent difference between the pure hydroxyapatite and all of the Mg-HA groups.Mg-HA bioceramics have no obvious cytotoxicity and may have good biocompatibility.