CO_3^(2-)掺杂纳米羟基磷灰石晶体的合成与表征

Synthesis and Characterization of CO_3^(2-) Doping Nano-Hydroxyapatite

CO32-掺杂是提高纳米羟基磷灰石(n-HA)生物活性的有效方法之一。以Ca(NO3)2·4H2O和Na3PO4·12H2O为主要原料,Na2CO3作为CO2-3来源,合成纳米碳羟基磷灰石(n-CHA)晶体。采用TEM,XRD,FTIR,RS对合成晶体形貌和结构进行表征。结果表明:合成的n-HA晶体长度约为60~80nm,宽度在20~30nm之间,形状为针状,具有良好的结晶度,与自然骨磷灰石形貌相似;n-CHA晶体随CO2-3掺入量的增加,结晶度降低;合成的n-CHA晶体的晶胞参数a值随着CO2-3加入量的增大不断收缩,但c值增大,参数比c/a值增大,符合B型取代(取代PO3-4)的晶胞参数变化规律。红外谱图中,872cm-1附近出现AB混合型取代(同时取代OH-,PO3-4)的CO2-3面外弯曲振动特征红外峰,同时CO2-3的不对称伸缩振动红外峰在1 454和1 420cm-1附近出现分裂峰,1 540cm-1附近出现弱CO2-3峰;1 122cm-1附近出现CO2-3对称伸缩振动拉曼峰,1 071cm-1附近出现CO2-3的B型替代特征拉曼峰,通过计算PO3-4,CO2-3,OH-拉曼峰的积分面积比PO3-4/CO2-3,OH-/CO23,PO3-4/OH-,表明CO2-3在替换时,先以B型为主,随着CO2-3掺入量的增加,发生A型替代(取代OH-)。实验结果表明,合成的磷灰石晶体为B型取代(取代PO3-4)为主的AB混合型取代的n-CHA。与人骨磷灰石晶体在形态、尺寸、晶体结构和生长方式上具有相似性,可称为类骨磷灰石。

CO32-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 CO2-3ions,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 20~30nm in diameter and 60~80nm in length,which are similar to natural bone apatite.And the crystallinity of n-CHA crystals decreases to the increment of CO2-3.Samples with more CO23 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 CO2-3,in accordance with crystal cell parameters change rule of type B replacement.In the AB mixed type(substitution OH-and PO3-4)CHA,IR characteristic peak of CO2-3out-of-plane bending vibration appears at 872cm-1,meanwhile,the asymmetry flexible vibration band is split into band at 1 454cm-1 and band at1 420cm-1,while weak CO23-peak appears at 1 540cm-1.CO2-3Raman peak of symmetric stretching vibration appears at 1 122cm-1.CO2-3B-type(substitution PO3-4)peak appeared at 1 071cm-1.Through the calculation of integral area ratio of PO3-4/CO2-3,OH-/CO2-3,and PO3-4/OH-,low quantity CO2-3is B-type and high quantity CO2-3is 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 in the shape,size,crystal structure and growth mode,the synthesized apatite crystals can be called a kind of bone-like apatite.