Shankhwar Nisha, Srinivasan A
Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039, India.
Department of Physics, Indian Institute of Technology Guwahati, Guwahati 781039, India.
Mater Sci Eng C Mater Biol Appl. 2016 May;62:190-6. doi: 10.1016/j.msec.2016.01.054. Epub 2016 Jan 22.
Multicomponent oxide powders with nominal compositions of (45-x)·SiO2·24.5CaO·24.5Na2O·6P2O5xFe2O3 (in wt.%) were prepared by a modified sol-gel procedure. X-ray diffraction (XRD) patterns and high resolution transmission electron microscope images of the sol-gel products show fully amorphous structure for Fe2O3 substitutions up to 2 wt.%. Sol-gel derived 43SiO2·24.5CaO·24.5Na2O·6P2O5·2Fe2O3 glass (or bioglass 45S5 with SiO2 substituted with 2 wt.% Fe2O3), exhibited magnetic behavior with a coercive field of 21 Oe, hysteresis loop area of 33.25 erg/g and saturation magnetization of 0.66 emu/g at an applied field of 15 kOe at room temperature. XRD pattern of this glass annealed at 850 °C for 1h revealed the formation of a glass-ceramic containing sodium calcium silicate and magnetite phases in nanocrystalline form. Temperature dependent magnetization and room temperature electron spin resonance data have been used to obtain information on the magnetic phase and distribution of iron ions in the sol-gel glass and glass-ceramic samples. Sol-gel derived glass and glass-ceramic exhibit in-vitro bioactivity by forming a hydroxyapatite surface layer under simulated physiological conditions and their bio-response is superior to their melt quenched bulk counterparts. This new form of magnetic bioglass and bioglass ceramics opens up new and more effective biomedical applications.
通过改进的溶胶 - 凝胶法制备了标称组成为(45 - x)·SiO₂·24.5CaO·24.5Na₂O·6P₂O₅·xFe₂O₃(重量百分比)的多组分氧化物粉末。溶胶 - 凝胶产物的X射线衍射(XRD)图谱和高分辨率透射电子显微镜图像显示,Fe₂O₃替代量高达2 wt.%时为完全非晶结构。溶胶 - 凝胶法制备的43SiO₂·24.5CaO·24.5Na₂O·6P₂O₅·2Fe₂O₃玻璃(或用2 wt.% Fe₂O₃替代SiO₂的生物玻璃45S5)在室温下15 kOe的外加磁场中表现出磁性行为,矫顽力为21 Oe,磁滞回线面积为33.25 erg/g,饱和磁化强度为0.66 emu/g。该玻璃在850℃退火1小时的XRD图谱显示形成了含有纳米晶形式的硅酸钠钙和磁铁矿相的微晶玻璃。利用温度依赖的磁化强度和室温电子自旋共振数据来获取关于溶胶 - 凝胶玻璃和微晶玻璃样品中铁离子的磁相和分布的信息。溶胶 - 凝胶法制备的玻璃和微晶玻璃在模拟生理条件下通过形成羟基磷灰石表面层表现出体外生物活性,并且它们的生物响应优于其熔融淬火的块状对应物。这种新型磁性生物玻璃和生物玻璃陶瓷开辟了新的、更有效的生物医学应用。
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