不同含量B_(2)O_(3)对生物活性玻璃支架力学性能与生物活性的影响

Different contents of B_(2)O_(3)affect mechanical properties and bioactivity of bioactive glass scaffolds

背景:生物活性玻璃骨修复材料具有骨结合能力、骨诱导能力及骨传导特性,但目前生物活性玻璃的性能尚不符合临床应用要求,添加硼元素有望改善生物活性玻璃的性能。目的:研究不同含量B_(2)O_(3)替代SiO_(2)对生物活性玻璃力学性能及生物活性的影响。方法:以含磷氮氧生物活性玻璃(成分为:SiO_(2)-CaO-ZnO-Na2O-Si3N4-P2O5)为基础,以B_(2)O_(3)部分替代其中的SiO_(2),采用高温熔融法烧制含B_(2)O_(3)质量分数分别为0%(A组),5%(B组),10%(C组),15%(D组)的基础玻璃(基础玻璃中SiO_(2)与B_(2)O_(3)的质量分数总和为41%),采用有机泡沫浸渍法制作多孔生物活性玻璃支架,利用万能力学试验机单轴压缩和三点弯曲法测试力学性能;将4组支架浸泡于模拟体液中,检测支架的降解性能,利用扫描电镜观察浸泡前后支架的形貌变化,以及X射线衍射分析浸泡前后的支架物相组成。结果与结论:①随着B_(2)O_(3)质量分数的增加,多孔生物活性玻璃支架的抗压强度与抗弯强度升高,4组支架的抗压强度与抗弯强度比较差异有显著性意义(P≤0.05);②浸泡于模拟体液中后,随着时间的延长,多孔生物活性玻璃支架逐渐降解;相同浸泡时间点下,随着B_(2)O_(3)质量分数的增加,支架的降解速率加快,4组支架的抗压强度与抗弯强度比较差异有显著性意义(P≤0.05);③浸泡于模拟体液后的扫描电镜显示,A、B组浸泡1 d后表面沉积大量的颗粒状物质,3 d后表面的颗粒状物质相互融合形成薄膜样沉积,7 d后表面的薄膜即相互融合成片,基本覆盖整个试件表面;C组浸泡1 d后表面形成薄膜样物质沉积,3 d后表面的薄膜即相互融合成片,基本覆盖整个试件表面;D组浸泡1 d后可见基本覆盖整个试件表面的片状物质;④浸泡于模拟体液中1 d后的X射线衍射分析显示,4组支架表面的沉积物为结晶态的羟基磷灰石;⑤B_(2)O_(3)替代部分SiO_(2)会增强多孔生物活性玻璃支架的力学性能、降解性能及体外矿化活性。

BACKGROUND:Bioactive glass bone repair material has bone-bonding ability,bone induction ability and bone conduction characteristics.However,the performance of bioactive glass does not meet the requirements of clinical application,and the addition of boron is expected to improve the performance of bioactive glass.OBJECTIVE:To study the effect of different contents of B_(2)O_(3)replacing SiO_(2)on the mechanical properties and bioactivity of bioactive glass.METHODS:Based on bioactive glass containing phosphorus nitrogen and oxygen(composition:SiO_(2)-CaO-ZnO-Na2O-Si3N4-P2O5),B_(2)O_(3)was used to partially replace the SiO_(2).The basic glass containing B_(2)O_(3)with a mass fraction of 0%(group A),5%(group B),10%(group C),and 15%(group D)was fired using the high-temperature melting method(the total mass fraction of SiO_(2)and B_(2)O_(3)in the basic broken glass was 41%).Porous bioactive glass scaffolds were fabricated by the organic foam impregnation method.Uniaxial compression and three-point bending method of universal mechanical testing machine were used to test mechanical properties.Four groups of scaffolds were immersed in simulated body fluids to detect the degradation performance of scaffolds.Scanning electron microscopy was used to observe the morphological changes of scaffolds before and after soaking.X-ray diffraction was used to analyze the phase composition of scaffolds before and after soaking.RESULTS AND CONCLUSION:(1)With the increase of the mass fraction of B_(2)O_(3),the compressive strength and bending strength of the porous bioactive glass scaffold increased,and there was a significant difference between the compressive strength and bending strength of the four groups(P≤0.05).(2)After soaking in simulated body fluids,the porous bioactive glass scaffolds degraded gradually with the extension of time.At the same soaking time point,the degradation rate of the scaffolds was accelerated with the increase of the mass fraction of B_(2)O_(3),and the compressive strength and bending strength of the scaffolds in the four groups were significantly different(P≤0.05).(3)Scanning electron microscopy after soaking in simulated body fluids showed that a large number of granular materials were deposited on the surface of group A and group B after soaking for 1 day.After 3 days,the granular materials on the surface fused with each other to form film-like deposits.After 7 days,the films on the surface fused with each other to form pieces,basically covering the entire surface of the specimen.After soaking for 1 day,film-like material deposition was formed on the surface of group C,and after 3 days,the films on the surface were fused into pieces,basically covering the whole surface of the specimen.After soaking for 1 day in group D,flake material covering the whole surface of the specimen could be seen.(4)X-ray diffraction analysis after 1 day of immersion in simulated body fluids showed that the deposits on the surface of the four groups of scaffolds were crystallized hydroxyapatite.(5)B_(2)O_(3)replacement of SiO_(2)can enhance the mechanical properties,degradation properties and in vitro mineralization activity of porous bioactive glass scaffolds.