硼硅酸盐生物活性玻璃多孔支架的制备

Na2O-CaO-SiO2-P2O5-B2O3系硼硅酸盐生物玻璃是一类具有良好生物活性和降解性能的组织工程材料.本研究中,采用有机泡沫浸渍法,乙醇作溶剂,乙基纤维素作添加剂,将硼硅酸盐玻璃粉体制备成具有三维连通网状结构的组织工程多孔支架.通过调节浆料的固相含量和乙基纤维素含量,改善坯体的涂覆量,在支架孔径为300～500um,孔隙率高于80%时,使支架抗压强度从0.03MPa提高到0.36MPa.根据蜂窝状结构模型分析,发现采用高强度玻璃,优化浆料是改善多孔材料结构和力学性能的有效途径.用该模型理论指导,由Na2O-CaO-SiO2-P2O5-B2O3系统制成的另一种硼硅酸盐玻璃支架,其抗压强度可达5～8MPa.实验表明有机泡沫浸渍法在制备组织工程支架中有广泛的应用前景.     

硼硅酸盐生物活性玻璃在直流电场下的体外矿化性能

硼硅酸盐生物活性玻璃具有良好的生物活性和骨传导性, 但大多数生物活性玻璃表现出非线性降解和矿化行为, 矿化性能会随着时间而减缓。电场作为一种外场辅助调节的方法, 能够干预玻璃的离子交换和扩散。本研究利用直流电场干预硼硅酸盐生物活性玻璃的体外矿化, 加快降解较慢阶段中硼硅酸盐生物玻璃的生物活性。将熔融法制备的成分为18SiO₂-6Na₂O-8K₂O-8MgO-22CaO-2P₂O₅-36B₂O₃的硼硅酸盐生物活性玻璃浸泡在SBF生理模拟液中, 施加0~90 mA的电流, 研究直流电场对硼硅酸盐生物玻璃降解及体外矿化性能的影响。研究结果表明, 施加电场不仅可以提高硼硅酸盐生物活性玻璃的降解率和离子释放量, 而且有利于玻璃网络水解和表面羟基化, 加速羟基磷灰石的生成。其中失重率比对照组提高了3%~5%, 硼和钙的离子释放量分别较对照组提高了2.3~2.9倍和1.9~2.3倍。对硼硅酸盐生物活性玻璃表面结构分析得出, 暴露在电场下的样品表面生成了磷灰石层。应用直流电场可以提高生物活性玻璃的降解及体外矿化性能, 为提升骨修复效果提供了一种新思路。     

含锶硼硅酸盐生物玻璃的降解性能及体外生物活性

研究了含锶硼硅酸盐玻璃的体外生物活性和降解性。采用熔融法制备不同锶含量(SrO含量为0、2%、4%、6%、8%、10%、12%(摩尔分数))的硼硅酸盐生物玻璃粉末,粒径范围为150～300μm。将各组玻璃样品浸泡在0.02mol/L的K2HPO4溶液中,置于37℃恒温条件下,进行体外生物矿化反应。通过对反应样品的质量损失以及浸泡液pH值进行测定,并用XRD、FTIR以及SEM对反应过程和反应后产物进行表征。结果表明,含锶的硼硅酸盐玻璃在体外生物矿化反应中被生物降解,并转化为含锶羟基磷灰石,具有很好的生物活性和降解性;同时也观察到玻璃中引入锶元素后,在一定程度上控制玻璃的降解速度,进而控制硼的溶出速度,从一定程度上避免硼溶出速度过高可能带来的风险;ICP的结构也表明,当SrO为6%(摩尔分数),样品中硼元素溶出的速度最低。因此,用锶的含量可控制硼硅酸盐玻璃的降解速度,这种方法将在组织工程领域具有广阔的应用前景。     

硅酸盐生物活性陶瓷研究进展

生物陶瓷经历了由惰性生物陶瓷如氧化铝和氧化锆陶瓷到可降解生物陶瓷如磷酸三钙陶瓷及具有生物活性的生物陶瓷如羟基磷灰石陶瓷的发展过程。近年来,随着再生医学研究和组织工程技术的发展,对生物材料的性能有了更高的要求,有学者提出了第三代生物材料的概念,认为新一代生物材料应该既具有生物活性,又可降解。研究发现,一些含硅的生物玻璃兼具有这两种特性,其生物活性体现在可以在模拟体液或体内环境中诱导形成类骨磷灰石,这种类骨磷灰石可以与骨组织形成键合。此外,研究显示这类生物玻璃材料具有促进细胞增殖和成骨基因表达的作用。但是,生物活性玻璃存在不易再加工成型,进一步热处理后生物活性和降解性会发生变化等问题。在生物玻璃研究的基础上,研究了一系列钙-硅体系的硅酸盐陶瓷,证实了这类生物陶瓷具有良好的生物活性和降解性,其生物活性和降解性与其化学组成有密切的关系,细胞实验显示这类硅酸盐陶瓷也具有促进细胞增殖分化和骨组织再生的作用,有望成为新一代骨修复材料。     

溶胶-凝胶法制备生物微晶玻璃的研究进展

溶胶-凝胶法是一种材料合成新工艺,现已广泛用作生物植入体、组织工程支架及药物载体的生物活性玻璃粉体、块体玻璃、多孔生物微晶玻璃与涂层的制备.简要介绍了溶胺-凝胶法制备生物微晶玻璃的工艺原理和优缺点,着重分析了其研究和应用现状,并阐述了其发展前景.     

含锶硼酸盐基生物玻璃经晶化处理后对其溶解性能及体外生物活性的影响

通过对含锶硼酸盐基玻璃进行微晶化处理,以考察该玻璃由玻璃态转化为晶态时体外生物活性和降解性的改变。采用熔融法制备不同锶含量(n(SrO)=0、2%、6%)的硼硅酸盐生物玻璃,然后在700℃/4h条件下微晶化处理,分别获得微晶化前后的试样。将各组玻璃及微晶化的样品浸泡在类似于生理模拟液的0.02mol/L的K2HPO4溶液中(以1g玻璃对应100mL浸泡液的比例),置于37℃恒温条件下,进行体外生物矿化反应。用XRD和FT-IR对反应后产物进行表征,并测定不同浸泡时间下样品的质量损失率以及浸泡液的pH值。结果表明,微晶化处理前后的含锶的硼硅酸盐玻璃试样在浸泡实验中都可以转化成含锶羟基磷灰石,即微晶化后的试样仍然具有体外生物活性;并且微晶化后试样的离子溶出速度能够减缓,降低了原玻璃相对骨组织生长来说的较高的降解速度,可以更加匹配骨组织生长的周期。因此,微晶化处理硼硅酸盐玻璃可实现对降解速度的调控,使该微晶化的生物玻璃有可能在骨组织修复中得到临床应用。     

有机泡沫浸渍法制备多孔生物玻璃支架的研究

选用58S生物活性玻璃粉体为原料,利用预先处理过的聚氨酯泡沫作为模板,制备了一种孔隙率高, 贯通性好,孔径可控的生物玻璃多孔支架. 并通过排水法、X射线衍射（XRD）、扫描电子显微镜（SEM）及傅里叶红外光谱（FTIR）等方法研究和表征了多孔支架的显气孔率、晶相组成、显微形貌和生物活性. 结果表明,浸料一次所得支架的显气孔率为93%左右,浸料二次下降为80%左右;在SBF溶液中,随着时间的延长,材料表面最初形成的颗粒状钙磷化合物逐渐矿化生成叶片状碳酸羟基磷灰石(HCA)层,表明该材料恒温37℃时具有较好的生物矿化性能和生物活性.     

介孔硼硅酸盐玻璃微球药物载体的制备及其性能表征

介孔二氧化硅微粒具有化学稳定性好、比表面积大和表面易修饰等特点, 作为药物载体具有良好的应用前景, 但其缺乏生物活性且生物降解缓慢等在一定程度上限制了它的应用领域。为克服这些缺陷, 寻找合适的药物载体已成为重要研究方向。与纯二氧化硅相比, 硼硅酸盐玻璃具有良好的生物活性和更高的降解速率。基于此, 本研究尝试合成介孔硼硅酸盐玻璃微球(MBGMs), 并表征了其在负载和释放抗肿瘤药物盐酸阿霉素(DOX)过程中的载体特性和材料降解引发的各种功能性离子的释放行为。结果表明BMGMs具有约25 mg/g的DOX负载量,引入硼不仅可以调控MBGMs的化学活性和降解速率, 而且较高硼含量的MBGMs可促进酸性条件下的药物释放, 具有一定的酸性响应性。此外, MBGMs可在模拟体液中释放SiO₄^4-、BO₃^3-和Ca²⁺等有益骨组织生长的功能性离子, 并诱导生成羟基磷灰石, 具备良好的离子缓释能力和体外矿化活性。因此, MBGMs作为一种新颖的药物载体材料, 既可作为药物和功能离子的双重负载, 又具有良好的生物活性和降解特性, 在病理性骨缺损修复领域具有良好的应用前景。     

硼硅酸盐生物活性玻璃在直流电场下的体外矿化性能（英文）

硼硅酸盐生物活性玻璃具有良好的生物活性和骨传导性,但大多数生物活性玻璃表现出非线性降解和矿化行为,矿化性能会随着时间而减缓。电场作为一种外场辅助调节的方法,能够干预玻璃的离子交换和扩散。本研究利用直流电场干预硼硅酸盐生物活性玻璃的体外矿化,加快降解较慢阶段中硼硅酸盐生物玻璃的生物活性。将熔融法制备的成分为18SiO_2-6Na_2O-8K_2O-8MgO-22CaO-2P_2O_5-36B_2O_3的硼硅酸盐生物活性玻璃浸泡在SBF生理模拟液中,施加0～90 m A的电流,研究直流电场对硼硅酸盐生物玻璃降解及体外矿化性能的影响。研究结果表明,施加电场不仅可以提高硼硅酸盐生物活性玻璃的降解率和离子释放量,而且有利于玻璃网络水解和表面羟基化,加速羟基磷灰石的生成。其中失重率比对照组提高了3%～5%,硼和钙的离子释放量分别较对照组提高了2.3～2.9倍和1.9～2.3倍。对硼硅酸盐生物活性玻璃表面结构分析得出,暴露在电场下的样品表面生成了磷灰石层。应用直流电场可以提高生物活性玻璃的降解及体外矿化性能,为提升骨修复效果提供了一种新思路。     

卵磷脂对生物活性玻璃表面改性的研究

采用卵磷脂对生物活性玻璃粉体表面进行改性处理, 并研究了生物活性玻璃与卵磷脂的相互作用. 热分析(TG/DSC)、傅立叶变换红外光谱（FTIR）分析表明, 卵磷脂在生物活性玻璃表面附着,通过氢键等弱键相互作用. 表面改性后的生物活性玻璃粉体与壳聚糖复合后, 复合材料的力学强度与未处理的相比有明显提高. 扫描电子显微镜(SEM)结果显示, 经处理后的生物活性玻璃粉体在壳聚糖中分散均匀, 两者结合紧密, 表明卵磷脂改性可以有效地提高生物活性玻璃粉体与壳聚糖有机基质的界面结合强度.     

Bioactive borosilicate glass scaffolds: in vitro degradation and bioactivity behaviors

Bioactive borosilicate glass scaffolds with the pores of several hundred micrometers and a competent compressive strength were prepared through replication method. The in vitro degradation and bioactivity behaviors of the scaffolds have been investigated by immersing the scaffolds statically in diluted phosphate solution at 37°C, up to 360 h. To monitor the degradation progress of the scaffolds, the amount of leaching elements from the scaffolds were determined by ICP-AES. The XRD and SEM results reveal that, during the degradation of scaffolds, the borosilicate scaffolds converted to hydroxyapatite. The compressive strength of the scaffolds decreased during degradation, in the way that can be well predicted by the degradation products, or the leachates, from the scaffolds. MTT assay results demonstrate that the degradation products have little, if any, inhibition effect on the cell proliferation, when diluted to a certain concentration ([B] <2.690 and pH value at neutral level). The study shows that borosilicate glass scaffold could be a promising candidate for bone tissue engineering material.     

In vitro evaluation of borate-based bioactive glass scaffolds prepared by a polymer foam replication method

Borate-based bioactive glass scaffolds with a microstructure similar to that of human trabecular bone were prepared using a polymer foam replication method, and evaluated in vitro for potential bone repair applications. The scaffolds (porosity = 72 ± 3%; pore size = 250–500 μm) had a compressive strength of 6.4 ± 1.0 MPa. The bioactivity of the scaffolds was confirmed by the formation of a hydroxyapatite (HA) layer on the surface of the glass within 7 days in 0.02 M K₂HPO₄ solution at 37 °C. The biocompatibility of the scaffolds was assessed from the response of cells to extracts of the dissolution products of the scaffolds, using assays of MTT hydrolysis, cell viability, and alkaline phosphatase activity. For boron concentrations below a threshold value (0.65 mM), extracts of the glass dissolution products supported the proliferation of bone marrow stromal cells, as well as the proliferation and function of murine MLO-A5 cells, an osteogenic cell line. Scanning electron microscopy showed attachment and continuous increase in the density of MLO-A5 cells cultured on the surface of the glass scaffolds. The results indicate that borate-based bioactive glass could be a potential scaffold material for bone tissue engineering provided that the boron released from the glass could be controlled below a threshold value.     

基于介孔硼硅酸盐生物活性玻璃微球的可注射复合骨水泥

以溶胶-凝胶法制备的介孔硼硅酸盐生物活性玻璃微球(MBGS)作为固相, 海藻酸钠(SA)溶液作为液相,开发了一种可注射复合骨水泥。对MBGS中氧化硼/氧化硅的比例对其质构性能及骨水泥的可操作性、抗压强度和生物活性的影响进行表征。实验结果表明, 随着硼含量的增加, MBGS的比表面积从161.71 m²/g增大至214.28 m²/g, 平均孔径以及总孔容也随之增长, 加速了玻璃相中钙离子的释放, 使得玻璃与SA的快速交联, 改善了骨水泥可操作性能和力学性能, 凝固时间由21 min缩短至9 min, 抗压强度由3.4 MPa提升至4.1 MPa, 体外矿化性能也随之提高。综合各方面性能表现, BC-30骨水泥兼具良好的可操作性能、力学性能和体外矿化能力, 是最合适的骨水泥组分。总之, 提高MBGS的质构性能是增强复合骨水泥的可操作性、抗压强度和生物活性的有效方法。     

介孔生物活性玻璃/脱钙骨复合支架的制备及性能研究

将介孔生物活性玻璃(MBG)与脱钙骨(DB)复合, 利用浸渍法制备出MBG/DB复合支架材料. 采用红外光谱(FTIR), 扫描电镜(SEM), X射线衍射(XRD), 电子万能材料试验机等方法对牛松质骨(CB)、DB、MBG/DB复合支架进行表征. 结果表明, CB经浸酸处理后制备的DB, 孔径大小在200~600μm范围内, 孔隙率约为71%, 抗压性能比CB明显降低(1.10±0.31)MPa, 而采用浸渍法制备的复合支架, 孔隙率降为40%左右, 而压缩强度明显提高(8.49± 2.14)MPa. 体外生物活性测试表明: 复合支架具有良好的生物活性.     

Transplantation of nano-bioglass/gelatin scaffold in a non-autogenous setting for bone regeneration in a rabbit ulna

Bioactive glass has been investigated for variety of tissue engineering applications. In this study, fabrication, in vitro and in vivo evaluation of bioactive glass nanocomposite scaffold were investigated. The nanocomposite scaffolds with compositions based on gelatin and bioactive glass nanoparticles were prepared. The apatite formation at the surface of the nanocomposite samples confirmed by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray powder diffraction analyses. The in vitro characteristics of bioactive glass scaffold as well as the in vivo bone formation capacity of the bioactive glass scaffold in rabbit ulnar model were investigated. The bioactive glass scaffold showed no cytotoxicity effects in vitro. The nanocomposite scaffold made from gelatin and bioactive glass nanoparticles could be deliberated as an extremely bioactive and prospective bone tissue engineering implant. Bioactive glass scaffolds were capable of guiding bone formation in a rabbit ulnar critical-sized-defect model. Radiographic evaluation indicated that successful bridging of the critical-sized defect on the sides both next to and away from the radius took place using bioactive glass scaffolds. X-ray analysis also proposed that bioactive glass scaffolds supported normal bone formation via intramembranous formation     

Foam-like scaffolds for bone tissue engineering based on a novel couple of silicate-phosphate specular glasses: synthesis and properties

Glass–ceramic scaffolds mimicking the structure of cancellous bone were produced via sponge replication technique by using a polyurethane foam as template and glass powder below 30 μm as inorganic phase. Specifically, a SiO₂-based glass of complex composition and its corresponding P₂O₅-based “specular” glass were used as materials for scaffolding. The polymeric sponge was thermally removed and the glass powders were sintered to obtain a replica of the template structure. The scaffolds were investigated and compared from a structural, morphological and mechanical viewpoint by assessing their crystalline phases, volumetric shrinkage, pores content and interconnection, mechanical strength. In addition, the scaffolds were soaked in acellular simulated body fluid to investigate their in vitro behaviour. The produced scaffolds have a great potential for bone reconstructive surgery because their features, such as shape, strength, bioactivity and bioresorption, can be easily tailored according to the end use.     

Bioactivity of degradable polymer sutures coated with bioactive glass

Novel bioactive materials have been prepared by coating violet resorbable Vicryl sutures with a bioactive glass powder derived from a co-precipitation method. Two techniques have been chosen for the composite preparation: pressing the sutures in a bed of glass powder and slurry-dipping of sutures in liquid suspensions of bioactive glass powders. The uniformity and thickness of the coatings obtained by the two methods were compared. The bioactivity of the sutures with and without bioactive glass coating was tested by soaking in an inorganic acellular simulated body fluid (SBF). The composite sutures were characterised by XRD, SEM and FTIR analyses before and after soaking in SBF solution to assess the formation of hydroxyapatite on their surfaces, which is a qualitative measure of their bioactivity. The possible use of bioactive sutures to produce tissue engineering scaffolds and as reinforcement of resorbable calcium phosphates is discussed.