Abstract：CO2-3 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 CO2-3 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 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 CO2-3 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 CO23-peak appears at 1 540 cm-1. CO2-3 Raman peak of symmetric stretching vibration appears at 1 122 cm-1. CO2-3 B-type (substitution PO3-4) peak appeared at 1 071 cm-1. Through the calculation of integral area ratio of PO3-4/CO2-3, OH-/CO2-3, and PO3-4/OH-, low quantity CO2-3 is B-type and high quantity CO2-3 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 in the shape, size, crystal structure and growth mode, the synthesized apatite crystals can be called a kind of bone-like apatite.
[1] Currey J. Nature, 2001, 414(6865): 699. [2] Fathi M H, Hanifi A, Mortazavi V. J. Mater. Proc. Tech., 2008, 202(1-3): 536. [3] JIANG Jia-chun, Lü Guo-yu, YAN Yong-gang, et al(蒋佳春, 吕国玉, 严永刚, 等). J. Mater. Eng.(材料工程): 2013, (4): 56. [4] Landi E, Tampieri A, Celotti G, et al. Biomaterials, 2005, 26(16): 2835. [5] Tang R, Hass M, Wu W, et al. J. Colloid Interface Sci., 2003; 60(2): 373. [6] Kokubo T, Takadama H. Biomaterials, 2006, 27(15): 2907. [7] Prakash Parthiban S, Yong Kim Ill, Koichi Kikuta, et al. Mater. Sci. Eng.: C, 2011, 31(7): 1383. [8] Neuman S Resende, Marcio Nele, Vera M M Salim. Thermochimica Acta, 2006, 451(1-2): 16. [9] Rey C, Collins B, Goehl T, Dickson I R, et al. Calcif. Tissue Int., 1989, 45(3): 157. [10] Elena L, Anna T, Giancarlo C, et al. Biomaterials, 2004, 25(10): 1763. [11] HUANG Zhi-liang, WANG Da-wei, LIU Yu, et al(黄志良, 王大伟, 刘 羽, 等). Chinese J. Inorg. Chem.(无机化学学报), 2002, 18(5): 469. [12] HUANG Zhi-liang, WANG Da-wei, LIU Yu, et al(黄志良, 王大伟, 刘 羽, 等). J. Inorg. Mater.(无机材料学报), 2002, 17(5): 959. [13] Shen J, Fan L, Yang J, et al. Osteoporosis Int., 2010, 21(1): 81. [14] RAN Xu, LI Yang, RAN Jun-guo, et al(冉 旭, 李 洋, 冉均国, 等). Rare. Metal. Mat. Eng.(稀有金属材料与工程), 2009, 38(z2): 863.
