造孔剂法制备多孔生物玻璃陶瓷的工艺研究

通过造孔剂法,以溶胶-凝胶法制备的生物玻璃58S和熔融法制备的生物玻璃45S5为原料,以NH4 HCO3与淀粉的混合物为造孔剂制备生物玻璃陶瓷.利用XRD和SEM等材料分析测试手段研究了烧成温度、造孔剂添加量、成型压力及45S5的用量对多孔材料显微结构、表面形貌、抗折强度的影响.结果表明:在成型压力20 MPa,造孔剂含量60％,烧成温度800℃及45S5的加入量10％的工艺参数下,制备出抗折强度达到4.5 MPa,孔隙率达到68.74％的珊瑚状结构的多孔生物玻璃陶瓷材料.     

溶胶-凝胶生物活性玻璃多孔支架的制备与性能的研究

通过溶胶—凝胶法合成制备了CaO-P2O5-SiO2系统溶胶—凝胶生物活性玻璃,并通过一定的造孔工艺将其制备成用作骨组织工程支架的多孔材料。采用体外模拟实验方法及DTA、SEM及FTIR等材料显微结构及性能研究手段分析研究了造孔剂种类、添加量对多孔材料的显微结构、表面形貌、抗折强度以及生物活性的影响。     

CaO-P2O5-SiO2系统溶胶-凝胶生物活性多孔材料的降解特性及生物活性研究

通过溶胶—凝胶法合成制备了CaO—-P2O5—SiO2系统溶胶—凝胶生物活性玻璃，并通过一定的烧结工艺将其制备成用作骨组织工程支架的多孔材料。采用生物材料的体外实验方法(in vitro)及DTA、XRD、SEM及FTIR等材料显微结构及性能研究手段分析研究了烧结温度对多孔材料的显微结构、生物活性和可降解性能的影响。     

溶胶-凝胶生物活性玻璃的纳米结构分析研究

利用溶胶-凝胶低温合成法制备了CaO-P2O5-SiO2系统生物活性玻璃骨修复及骨组织工程材料.利用SEM、BET及XRD等方法对溶胶-凝胶生物活性玻璃的微观结构及其组成对材料微观结构的影响进行了分析,并同目前已临床应用的45S5生物活性玻璃进行了比较.研究发现由溶胶-凝胶法制备的生物活性玻璃是由纳米级微球构成,其高比表面积是由其纳米微球之间的孔隙所致.这种高比表面积对于提高材料的表面吸附能力及生物矿化功能具有重要作用.根据等大球体最紧密堆积原理建立了溶胶-凝胶生物活性玻璃纳米孔隙尺寸近似计算模型,并对其孔隙结构进行了分析计算.     

壳聚糖/生物活性玻璃多孔复合支架的制备及界面增强作用

采用卵磷脂作为表面活性剂对溶胶-凝胶生物玻璃进行表面改性,并采用冷冻干燥法制备用于骨和软骨组织工程的壳聚糖/生物活性玻璃复合多孔支架(chitosan/bioglass porous composite scaffolds,CS/BGS),观察CS/BGS的显微形貌并测定抗压强度,探讨生物玻璃的表面改性对CS/BGS显微结构及力学强度的影响。研究表明:采用冷冻干燥法可以制备具有一定强度的三维连通的CS/BGS,且孔隙率达到90%以上。通过对生物玻璃表面改性可以在一定程度上提高CS/BGS的抗压强度。     

烧结法制备硼酸盐微晶玻璃支架及其体外生物活性

采用熔融法制备组成(摩尔分数)为24.5%Na2O-24.5%CaO-6%P2O5-45%B2O3的硼酸盐微晶玻璃。选取粒径为300～400μm的硼酸盐微晶玻璃颗粒,用烧结法制备硼酸盐微晶玻璃支架。采用质量损失分析、X射线衍射和电子扫描显微镜等手段分析玻璃支架与模拟体液(simulated body fluid,SBF)溶液的反应过程,研究其生物活性和生物降解性,同时将其与烧结法制备的45S5玻璃支架进行比较。结果表明:与45S5玻璃支架相比,硼酸盐微晶玻璃支架具有更好的生物降解性能和生物活性。硼酸盐微晶玻璃中的玻璃相在SBF中降解速率快,支架表面快速形成羟基磷酸钙的沉积。硼酸盐微晶玻璃中β-NaCaPO4晶相的降解速率慢,可以使支架材料保持较持久的强度。这种双重反应特性使支架材料的降解速率与骨组织的生长速率相配,使支架材料在骨组织工程上具有良好的应用前景。     

用硅烷偶联剂处理生物玻璃表面及其复合支架的制备

为了改善溶胶-凝胶生物活性玻璃与高分子材料的相容性,用硅烷偶联剂氨丙基三乙氧基硅烷对生物活性玻璃进行表面处理,并用X射线光电子能谱对处理后的生物活性玻璃的表面进行元素分析.结果表明:偶联剂通过Si-O-Si键被引入到生物活性玻璃表面.用处理后的生物活性玻璃与壳聚糖-明胶复合制备了多孔支架.扫描电子显微镜观察发现:复合多孔支架的两相相容性好,界面结合紧密;支架的孔隙连通、排列规则.力学测试表明:改性后的溶胶-凝胶生物活性玻璃与壳聚糖-明胶制备的复合支架力学性能得到明显改善.     

溶胶-凝胶法制备生物活性玻璃陶瓷的研究

采用溶胶-凝胶法制备前驱体粉体,经高温煅烧制备了名义化学组成为MgO4．6,CaO44．9,SiO234．2,P2O516．3,CaF20．5(质量分数)的磷灰石-硅灰石生物活性玻璃陶瓷。用造孔工艺制备了其多孔型材料。通过实验观察、差热和热重分析。体积密度和气孔率的测量,粒度测试、X射线衍射分析。扫描电镜观测,FTIR转换红外光谱分析等方法。研究了玻璃陶瓷前驱体粉末的溶胶-凝胶制备工艺条件,玻璃陶瓷的烧结工艺条件;分析了材料的晶相结构和显微结构。实验结果表明：溶胶-凝胶法可制备出微细的非晶态前驱体粉末,经烧结后玻璃陶瓷主晶相为磷灰石及β-硅灰石。造孔后。多孔型材料具有良好的贯通孔隙结构：微观孔隙约2～3 μm,宏观孔隙约300～400 μm。鉴于其晶相组成及良好的微观结构,通过新型溶胶-凝胶工艺开发的生物活性玻璃陶瓷材料可望被用于骨修复材料及骨组织工程支架材料。     

发泡剂对钼渣多孔玻璃性能的影响

采用高温熔融直接发泡制备钼渣多孔玻璃,通过研究不同发泡剂对钼渣多孔玻璃性能的影响,确定最佳发泡剂,研究了最佳发泡剂含量对钼渣多孔玻璃气孔率和抗折强度的影响.结果表明,BaCO3在本体系中发泡效果最好,随着发泡剂BaCO3含量的增加,钼渣多孔玻璃气孔率和抗折强度均发生变化,当BaCO3含量10%wt时,气孔率最高,为16.8%.X射线衍射分析钼渣多孔玻璃有少量石英残留,显微结构表明孔结构基本上不连通,为闭孔材料.     

MgO对多孔堇青石材料组成结构的影响

以菱镁矿轻烧粉、废弃水口和硅灰为原料制备多孔堇青石材料,研究分析菱镁矿轻烧粉中氧化镁对制备多孔堇青石材料致密度、结晶相组成及显微结构的影响。用XRD法和SEM法表征多孔堇青石材料中的结晶相和显微结构。结果表明:利用高温固相反应烧结,可以制备出以堇青石为主晶相的多孔堇青石材料。但菱镁矿轻烧粉的过量引入会降低多孔堇青石材料的孔隙率,导致合成材料中镁橄榄石相增多。     

Studies on novel bioactive glasses and bioactive glass-nano-HAp composites suitable for coating on metallic implants

A series of novel zinc oxide (ZnO) containing bioactive glass compositions in SiO₂-Na₂O-CaO-P₂O₅ system and composite with hydroxyapatite (HAp) nano-particles were developed and applied as coating on Ti-6Al-4V substrates. The bioactive glasses and their composites were also processed to yield dense scaffolds, porous scaffolds and porous bone filler materials. The coating materials and the coatings were characterized and evaluated by different in vitro techniques to establish their superior mechanical properties. The cytotoxicity test of the coating material, porous and dense scaffolds and coated specimens showed non-cytotoxicity, biocompatibility and promising in vitro bioactivity for all tested samples. The dissolution behaviour studies of the bioactive glasses and the composites in simulated body fluid showed promising in vitro release pattern and bioactivity for all tested samples. Addition of nanosized HAp improves mechanical properties of the bioactive glass coating without affecting the in vitro bioactivity.     

骨修复用生物玻璃研究进展

生物活性玻璃和生物微晶玻璃因其优异的生物活性及组分与性能可设计性而引起广泛关注,人们力图在其基础上研制出性能优良的骨修复材料.近来有报道发现特定组分的玻璃能激活基因从而促进骨组织再生,为生物玻璃的应用开拓了新的领域.本文综述了目前的生物玻璃及生物微晶玻璃体系、组分与制备工艺对其理化性能和生物活性的影响、生物活性的评价方式及其活性机理.     

Bioactivity and biodegradability of high temperature sintered 58S ceramics

Bioactive glasses are often considered in bone tissue engineering applications where mechanical strength is essential. As such, bioactive glass scaffolds are often sintered to improve mechanical strength. However, sintering can lead to crystallization, which reduces bioactivity and biodegradability. It has generally been considered that amorphous biomaterials exhibit better bioactivity. However, the in-vitro bioactivity and biodegradability of the sintered 58S made from initial amorphous powder and partially crystalline powder with the same chemical compositions (60SiO₂-36CaO-4P₂O₅ (mol%)) have not been compared before.In this study, 58S bioactive glass (fully amorphous) and glass-ceramic (partially crystallized) powders were synthesized using the sol-gel process, followed by heat-treating at 600 °C for 3 h (calcination). The powders were mixed with carboxymethyl cellulose solution as a binder, shaped in a cylindrical mold, dried, and then sintered at 1100 °C for 5 h. The in-vitro bioactivity and biodegradability of the sintered samples were assessed in simulated body fluid (SBF) for times up to 28 days. The specimens were investigated before and after immersion in SBF using X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM), and Fourier transform infrared spectroscopy (FT-IR). The In-vitro bioactivity and biodegradability rate of the sintered 58S produced from the glass ceramic powder were higher than that from fully amorphous powder. This study shows that the initial structure after calcination is important and affects the subsequent crystallization during sintering. Therefore, crystallinity and formation of hydroxyapatite after calcination are important controlling mechanisms that can increase the bioactivity and biodegradability rate of sintered 58S.     

骨修复用生物玻璃的研究现状及其发展趋势

生物活性玻璃和生物微晶玻璃因其优异的生物活性及组分与性能的可设计性而引起广泛关注，人们力图在此基础上研制出性能优良的骨修复材料。笔者综述了目前生物玻璃及生物微晶玻璃体系、组分及其活性机理，探讨了其在医学领域的应用及其发展趋势。     

Effect of low temperature crystallization on 58S bioactive glass sintering and compressive strength

Mesoporous glass 58S (60SiO₂, 36CaO, 4P₂O₅ mol.%) has excellent bioactivity, biocompatibility, and forms strong bonds with bone making it attractive for implants. Mesoporous bioactive glass 58S powder is typically consolidated through sintering in order to produce an implant with sufficient strength to withstand the in vivo loads. However, heating the glass often leads to crystallinity, which is undesirable because it can reduce bioactivity. Hence, there is a trade-off between minimising crystallinity and maximising glass strength. Even at relatively low temperatures, it has been suggested that segregation of calcium and phosphate from silica within the glass can lead to crystallization. In this work, we confirm the occurrence of low temperature segregation in bioactive glass 58S using electron microscopy with elemental mapping. We probe how segregation affects the material properties of post-sintered glasses via comparison to a glass where phase separation is prevented via addition citric acid to the parent sol.     

Enhancing In Vitro Bioactivity of Melt‐Derived 45S5 Bioglass® by Comminution in a Stirred Media Mill

45S5 Bioglass^® (45S5 BG) is a frequently applied Type A bioactive material, capable of forming an inherent bond to bone and soft tissue. Currently, applied melt‐derived bioactive glass powders (BG) exhibit particle sizes between a few to several hundred micrometers. Recent studies on nanometer‐sized bioactive glasses (nBGs), produced by bottom‐up methods like sol–gel processing or flame spray pyrolysis, have indicated their great potential for several biomedical applications. In this study, the feasibility of top‐down processing starting from bulk 45S5 BG by wet comminution in a stirred media mill was investigated. The products were assessed by in vitro hydroxycarbonate apatite (HCAp) formation in simulated body fluid, which is a marker for bioactive behavior. The study reveals the paramount influence of the used solvent for a successful top‐down processing: In comparison with the as‐received material bioactivity is lost for powders processed in water, preserved for comminution in ethanol and increased for powders processed using the alcohols n‐butanol, n‐pentanol, and n‐hexanol. It was also found that only for the latter solvents, the chemical composition of the glass is maintained during comminution. Flake‐like, slightly porous particles with specific surface areas of ~25–30 m²/g are obtained. Thus, the presented comminution approach offers a convenient technique to process 45S5 BG with enhanced bioactivity.     

Er3+/Yb3+ co-doped bioactive glasses with up-conversion luminescence prepared by containerless processing

Er³⁺/Yb³⁺ co-doped bioactive glasses were prepared via containerless processing in an aerodynamic levitation furnace. The as-prepared glasses were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) equipped with energy dispersive X-Ray spectroscopy (EDX). The up-conversion luminescence of as-prepared glasses was measured using an Omni- 3007 spectrometer. Furthermore, the in vitro bioactivity was evaluated by soaking the materials in simulated body fluid, and the biocompatibility was evaluated in MC3T3-E1 cell culture.The results show that containerless processing is a unique method to prepare homogeneous rare earth doped bioactive glasses. The obtained Er³⁺/Yb³⁺ co-doped glasses show green and red up-conversion luminescence at the excitation of 980 nm laser. The XRD analysis confirmed that calcium silicate powders, as starting materials, were completely transformed from the original multi-crystalline phase (CS-P) into the amorphous-glassy phase (CS-G, EYS, LCS) via containerless processing. The SEM observation combined with EDX and FTIR analyses showed that the as-prepared glasses were bioactive. The cell proliferation assay also revealed that the as-prepared glasses were biocompatible and nontoxic to MC3T3-E1 cells. This study suggests that the luminescent bioactive glasses prepared by containerless processing could be used for studying biodegradation of bone implantation materials.     

Bioactive Glasses: From Macro to Nano

Bioactive glasses play an important role for the bone defects treatment. Forty years ago, it was discovered the first bioactive glass, Bioglass^®, obtained by melting and used in Orthopedics and Dentistry. Twenty years ago, another family of bioactive glasses obtained by solgel processing was reported. Solgel glasses exhibit high textural properties and quicker bioactive response than melt glasses. However, their presence in the market is scarce which could be explained considering that the improvements they bring do not justify the costs of their translation to product. In the last decade, so-called template glasses exhibiting greater bioactivity than solgel glasses were described. These glasses display high pore volume and ordered mesopore structure, which makes them optimal candidates for hosting biologically active substances. For these characteristics, template glasses are being considered ideal candidates for the scaffolds manufacture used in bone engineering. This article shows the main features of three families of bioactive glasses and the importance of their nanostructure in the bioactivity. We demonstrate here that glasses with identical composition may exhibit very different properties, specifically bioactivity, as a function of their nanostructure. This fact demonstrates the importance of controlling this nanostructure in the design of new bioactive materials for bone regeneration.