Liao Jian-Guo, Li Yan-Qun, Duan Xing-Ze, Liu Qiong
Guang Pu Xue Yu Guang Pu Fen Xi. 2014 Nov;34(11):3011-4.
CO3(2-) doping is an effective method to increase the biological activity of nano-hydroxyapatite (n-HA). In the present study, calcium nitrate and trisodium phosphate were chosen as raw materials, with a certain amount of Na2CO3 as a source of CO-3(2-) ions, to synthesize nano-carbonate hydroxyapatite (n-CHA) slurry by solution precipitation method. The structure and micro-morphology of n-CHA were characterized by transmission electron microscope (TEM), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR) and Raman spectroscopy (RS). The results revealed that the synthetic n-HA crystals are acicular in nanometer scale and have a crystal size of 20-30 nm in diameter and 60-80 nm in length, which are similar to natural bone apatite. And the crystallinity of n-CHA crystals decreases to the increment of CO3(2-). Samples with more CO3(2) have composition and structure more similar to the bone apatite. The value of lattice parameters a decreases, value of c increases, and c/a value increases with the increase in the amount of CO3(2-), in accordance with crystal cell parameters change rule of type B replacement. In the AB mixed type (substitution OH- and PO4(3-)) CHA, IR characteristic peak of CO3(2-) out-of-plane bending vibration appears at 872 cm(-1), meanwhile, the asymmetry flexible vibration band is split into band at 1 454 cm(-1) and band at 1 420 cm(-1), while weak CO3(2)-peak appears at 1 540 cm(-1). CO3(2-) Raman peak of symmetric stretching vibration appears at 1 122 cm(-1). CO3(2-) B-type (substitution PO4(3-)) peak appeared at 1 071 cm(-1). Through the calculation of integral area ratio of PO4(3-)/ CO3(2-), OH-/CO3(2-), and PO4(3-)/OH-, low quantity CO3(2-) is B-type and high quantity CO3(2-) is A-type (substitution OH-). The results show that the synthesized apatite crystals are AB hybrid substitued nano-carbonate hydroxyapatite, however B-type replacement is the main substitute mode. Due to similarity inthe shape, size, crystal structure and growth mode, the synthesized apatite crystals can be called a kind of bone-like apatite.
碳酸根（CO₃²⁻）掺杂是提高纳米羟基磷灰石（n-HA）生物活性的有效方法。在本研究中，选择硝酸钙和磷酸三钠作为原料，以一定量的碳酸钠作为CO₃²⁻离子源，通过溶液沉淀法合成纳米碳酸羟基磷灰石（n-CHA）浆料。采用透射电子显微镜（TEM）、X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）和拉曼光谱（RS）对n-CHA的结构和微观形貌进行了表征。结果表明，合成的n-HA晶体为纳米级针状，晶体尺寸为直径20-30nm，长度60-80nm，与天然骨磷灰石相似。随着CO₃²⁻含量的增加，n-CHA晶体的结晶度降低。CO₃²⁻含量较高的样品的组成和结构与骨磷灰石更相似。晶格参数a值减小，c值增大，c/a值随着CO₃²⁻含量的增加而增大，符合B型置换的晶胞参数变化规律。在AB混合型（取代OH⁻和PO₄³⁻）CHA中，CO₃²⁻的面外弯曲振动红外特征峰出现在872cm⁻¹处，同时不对称伸缩振动带分裂为1454cm⁻¹处的谱带和1420cm⁻¹处的谱带，而在1540cm⁻¹处出现弱的CO₃²⁻峰。CO₃²⁻的对称伸缩振动拉曼峰出现在1122cm⁻¹处。CO₃²⁻的B型（取代PO₄³⁻）峰出现在1071cm⁻¹处。通过计算PO₄³⁻/CO₃²⁻、OH⁻/CO₃²⁻和PO₄³⁻/OH⁻的积分面积比，低含量的CO₃²⁻为B型，高含量的CO₃²⁻为A型（取代OH⁻）。结果表明，合成的磷灰石晶体为AB混合取代的纳米碳酸羟基磷灰石，然而B型置换是主要的取代方式。由于在形状、尺寸、晶体结构和生长方式上的相似性，合成的磷灰石晶体可称为一种类骨磷灰石。
