CEMHTI CNRS UPR3079, 1D Av. de la recherche scientifique, 45071 Orléans Cedex 2, France.
Campus Universitaire-Ait Melloul, Université Ibn Zohr, Agadir, Morocco; LGP, Chemical Department, Faculty of Sciences, Université Ibn Zohr, B.P. 8106, Agadir, Morocco.
J Mech Behav Biomed Mater. 2018 Oct;86:284-293. doi: 10.1016/j.jmbbm.2018.06.023. Epub 2018 Jun 22.
Bioactive glasses are able to bond to bone through formation of carbonated hydroxyapatite in body fluids. However, because of their poor strength their use is restricted to non-load-bearing applications. The effects of nitrogen addition on the physical and mechanical properties and structure of bioactive oxynitride glasses in the system Na-Ca-Si-P-O-N have been studied. Glasses with compositions (mol.%): 29NaO-13.5CaO-2.5PO-(55 -3x)SiO-xSiN (x is the no. of moles of SiN) were synthesised with up to 1.5 at% P and 4.1 at% N. A novel 3-step process was used for addition of P and N and this proved successful in minimising weight losses and producing homogeneous glasses with such high SiO contents. The substitution of 4.12 at% N for oxygen results in linear increases in density (1.6%), glass transition temperature (6%), hardness (18%) and Young's modulus (74%). Vickers Indentation Fracture (VIF) resistance (K) was calculated from various relationships depending on the load, indent diagonal, crack lengths and Young's modulus to hardness (E/H) ratio. Firstly, Meyer's index n is calculated from the slope of the logarithmic plot of load versus indent diagonal. Then by comparing the experimental slopes of the logarithmic plots of crack lengths versus load it is concluded that the cracking mode is Radial Median type. The substitution of 4.12 at% N for oxygen results in an increase in K of 40%. These increases in properties are consistent with the incorporation of N into the glass structure in three-fold coordination with silicon which results in extra cross-linking of the glass network. The structure of these bioactive oxynitride glasses was investigated by solid state nuclear magnetic resonance (MAS NMR) of P and Si. The structure reveals that all the N atoms are bonded to Si atoms with the formation of SiON, SiON and Q structural units with extra bridging anions at the expense of Q units. The bioactivity of the glasses has been evaluated by soaking them in simulated body fluid (SBF) and results confirm that all these oxynitride glasses are bioactive. Cytotoxicity tests based on different concentrations of these bioactive glass powders in a cell growth environment have also shown that they are not cytotoxic.
生物活性玻璃能够通过在体液中形成碳酸羟基磷灰石与骨结合。然而，由于其强度较差，它们的使用仅限于非承重应用。本研究探讨了氮的添加对 Na-Ca-Si-P-O-N 系统中生物活性氧氮化物玻璃的物理力学性能和结构的影响。用组成（摩尔%）为：29NaO-13.5CaO-2.5PO-(55-3x)SiO-xSiN（x 为 SiN 的摩尔数）的玻璃合成了高达 1.5 at% P 和 4.1 at% N。采用了一种新颖的三步法添加 P 和 N，这一方法成功地减少了重量损失，并在如此高的 SiO 含量下生产出了均匀的玻璃。用 4.12 at% N 替代氧会使密度（1.6%）、玻璃化转变温度（6%）、硬度（18%）和杨氏模量（74%）呈线性增加。维氏压痕断裂（VIF）阻力（K）是根据不同的关系计算的，这些关系取决于载荷、压痕对角线、裂纹长度和杨氏模量与硬度（E/H）的比值。首先，从载荷与压痕对角线的对数图的斜率计算出迈尔指数 n。然后，通过比较裂纹长度与载荷的对数图的实验斜率，可以得出裂纹模式为径向中值型。用 4.12 at% N 替代氧会使 K 增加 40%。这些性能的提高与 N 以三配位方式掺入玻璃结构中，导致玻璃网络的额外交联一致。通过固态核磁共振（MAS NMR）对 P 和 Si 的研究，研究了这些生物活性氧氮化物玻璃的结构。结构表明，所有的 N 原子都与 Si 原子键合，形成 SiON、SiON 和 Q 结构单元，同时以 Q 单元为代价形成额外的桥接阴离子。通过将玻璃浸泡在模拟体液（SBF）中来评估玻璃的生物活性，结果证实所有这些氧氮化物玻璃都是生物活性的。基于这些生物活性玻璃粉末在细胞生长环境中的不同浓度的细胞毒性测试也表明它们没有细胞毒性。
