A/W生物微晶玻璃材料的研究进展

生物活性玻璃陶瓷材料由于能够与活体组织自发产生紧密的化学键合而成为骨修复材料中的重要分支,其中A/W生物微晶玻璃更是由于在保持良好生物活性的基础上,力学性能接近甚至超过自然骨而作为承重的生物活性材料应用于临床.系统介绍了A/W生物微晶玻璃的制备方法、生物活性和力学性能,并展望了A/W生物微晶玻璃今后的研究发展方向.     

碳/碳复合材料表面改性及其生物响应特性

碳/碳复合材料继承了碳材料固有的生物相容性,它具有优异的力学性能,特别是它的弹性模量与人骨相当,是一种具有潜力的骨修复和替代生物材料.但是由于碳/碳复合材料为生物惰性材料,其与骨组织表面仅仅是机械结合,通过表面改性,可在其表面构筑生物活性涂层以提高其生物活性和减少碳颗粒的释放.本文在综述了碳/碳复合材料表面生物活性涂层制备方法及其生物学响应特性的基础上,分析了目前研究中存在的问题,提出一些解决的办法,并展望了其发展前景.     

壳聚糖类复合材料应用于骨修复的研究进展

壳聚糖是天然多糖类高分子化合物甲壳素的脱乙酰产物,具有良好的生物相容性、可降解性和生物活性,可作为骨修复材料,并可应用于骨组织工程材料中的三维生长支架,作为种子细胞或活性生长因子的生物载体材料.综述了壳聚糖类复合材料在骨填充修复材料、骨组织工程和软骨组织工程方面应用的状况及前景.     

激活基因的玻璃

三十年前发现，生物玻璃能与骨形成骨键结合。这种特殊的材料已经有超过15年的临床应用，并在数以千计的成功病例。研究表明，骨的键合及骨再生和修复（骨形成作用）涉及玻璃表面的离子快速交换反应、生物活性表面反应层的成核和生长、由可溶硅和钙组成的临界浓度的离子溶解产物的释放。生物活性玻璃的分子生物学机理研究表明，它的生物活性响应看起来是由基因控制的。具有骨促进作用的A类生物活性玻璃通过直接对那些调节诱发细胞周期开始和进程的基因的直接控制，从而加强了其骨形成和促进作用。不能够形成新骨的细胞从细胞总体中被消除，这一特征是当成骨细胞在生物惰性材料或者B类生物活性材料培养时所没有的。骨前细胞细胞周期的基因调控生物学结果是成骨细胞的快速繁殖和分裂，这也导致了骨的迅速再生。对生物活性玻璃基因基础的理解，可以为设计新一代活化基因的玻璃材料，以及新一代活化基因的组织工程用生物降解支架提供重要的依据。如果我们能用玻璃激活基因，可以肯定，有一天我们就能用玻璃来控制基因。     

C/C复合材料表面生物活性涂层的研究进展

C/C复合材料继承了碳材料固有的生物相容性,具有优异的力学性能,尤其是其弹性模量与人骨相当,且该材料的三维多孔结构有利于细胞的进入、生长和发育,因此在骨修复和骨替代方面有较好的应用前景。但C/C复合材料亲水性能较差,且为生物惰性材料,因此改性C/C复合材料表面生物活性被广泛研究。本文综述了近年来在C/C复合材料表面制备不同生物活性涂层的研究进展,并提出存在的问题和未来展望。     

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。     

注射式骨修复多孔复合材料的性能研究

骨缺损在临床上是一种常见现象,通过制备纳米羟基磷灰石/聚酰胺66复合材料粉末,并以纳米羟基磷灰石/聚酰胺66和海藻酸钠的混合粉末作为主要固体成分,以聚乙烯醇水溶液为主要液相,通过混合搅拌制备了注射式骨修复多孔复合材料.通过X射线衍射(XRD)、红外(IR)、扫描电镜(SEM)和透射电镜(TEM)对材料的性能进行表征,表征结果表明制备的注射式骨修复材料中含有与天然骨中相似的无机成分,具有好的生物相容性和生物活性.材料的固化时间与材料的固液比、比表面积和温度等因素有关.通过调整材料的固相、液相比例,可以获得不同固化时间和不同孔隙率的骨修复材料.     

微纳米生物活性玻璃的细胞基因激活性能研究

微纳米生物材料目前已成为生物医用材料领域一个研究热点和难点。大量研究表明具有微纳米结构特征的生物材料表现出了积极的生物学响应。生物活性玻璃(BG)具有较高的生物活性、生物相容性,是一类重要的骨修复材料。而微纳米生物活性玻璃(MNBG)因其具有特殊的形态结构和理化性能,引起众多研究者的关注。但是目前对MNBG的研究还主要集中在制备、表征以及其表面类骨羟基磷灰石矿物在SBF溶液中的形成活性等方面,关于MNBG的细胞相容性以及基因激活性能方面的研究还鲜有报道。通过溶胶-凝胶法结合模板仿生技术合成了具有特殊微纳米结构和形态的MNBG,并将其浸提液与MG-63细胞共培养,研究生物玻璃溶出物对细胞增殖,成骨相关基因和蛋白表达的影响,结果证明相比于传统的熔融法制备的生物玻璃(45S5)浸提液,MNBG浸提液能够明显促进细胞增殖,激活细胞成骨相关基因,上调相关蛋白的表达,为设计和制备具有基因介导作用的新型生物活性玻璃骨修复材料提供了理论依据。     

医用钛表面生物活性化研究

钛及钛合金具有优良的生物相容性和机械性能,已应用于临床,尤其是用作骨替换与修复材料.但是,钛属于生物惰性材料,不能与骨组织形成化学键合或称骨键合.通过表面改性可使其在生理环境具有诱导羟基磷灰石在表面自发生长的能力,即生物活性化.这是当今生物医用材料研究的热点领域之一.本文评述了钛表面生物活化的研究现状,简要总结了本课题组在这方面的研究工作.     

磷酸镁/PBS/小麦蛋白复合骨修复材料

采用共沉淀法合成磷酸镁, 将磷酸镁(MP)、聚丁二酸丁二醇酯(PBS)和小麦蛋白(WP)进行复合, 制备出MP/PBS/WP复合骨修复材料。通过体外降解、生物活性以及细胞培养等实验对复合材料的理化性能及细胞相容性进行了研究。结果显示: MP/PBS/WP复合材料在Tris-HCl缓冲液中浸泡10 d后, 溶液pH从7.4上升至7.51, 浸泡12 w后, 其降解率达到58.43wt%; 复合材料在模拟体液中浸泡10 d后, 其表面形成磷灰石层; 复合材料能促进MC3T3-E1细胞的增殖与分化。结果表明: MP/PBS/WP复合材料具有优良的降解性、生物活性和细胞相容性, 有望成为一种新型骨修复材料。     

Controlling ion release from bioactive glass foam scaffolds with antibacterial properties

Bioactive glass scaffolds have been produced, which meet many of the criteria for an ideal scaffold for bone tissue engineering applications, by foaming sol-gel derived bioactive glasses. The scaffolds have a hierarchical pore structure that is very similar to that of cancellous bone. The degradation products of bioactive glasses have been found to stimulate the genes in osteoblasts. This effect has been found to be dose dependent. The addition of silver ions to bioactive glasses has also been investigated to produce glasses with bactericidal properties. This paper discusses how changes in the hierarchical pore structure affect the dissolution of the glass and therefore its bioactivity and rate of ion delivery and demonstrates that silver containing bioactive glass foam scaffolds can be synthesised. It was found that the rate of release of Si and Ca ions was more rapid for pore structures with a larger modal pore diameter, although the effect of tailoring the textural porosity on the rate of ion release was more pronounced. Bioactive glass scaffolds, containing 2 mol% silver, released silver ions at a rate that was similar to that which has previously been found to be bactericidal but not high enough to be cytotoxic to bone cells.     

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。     

Microwave energy-assisted formation of bioactive CaO–MgO–SiO<Subscript>2</Subscript> ternary glass from bio-wastes

Regeneration technique is extensively being sought after as a means of achieving bone repair without adverse immunological response. Silicate-based bioactive glasses containing Mg are gaining increasing attention for their biocompatibility. The current work has been focused on designing a facile and economic route using bio-wastes for synthesizing bioactive glasses in the CaO–MgO–SiO₂ system. Rice husk ash (RHA) obtained from burning rice husk was used as silica source, while Ca was extracted from eggshells for preparing the glass through a modified sol–gel approach. The gel formed was irradiated in microwave before sintering at 950^°C for 3 h. Thereafter, bioactivity test was conducted on the samples in simulated body fluid (SBF) at physiological conditions for a maximum of 14 days. Characterization of samples were performed before and after immersion in SBF to evaluate the composition, morphology and phases present in the glass using energy-dispersive X-ray analysis, scanning electron microscopy and X-ray diffraction. Apatite formation was confirmed using Fourier transform infrared spectroscopy. Results obtained showed the presence of diopside, wollastonite and pseudo-wollastonite as major bioactive phases. Hydroxyapatite formed on the material within 3 days in SBF, indicating good bioactivity.     

Influence of SrO substitution for CaO on the properties of bioactive glass S53P4

Commercial melt-quenched bioactive glasses consist of the oxides of silicon, phosphorus, calcium and sodium. Doping of the glasses with oxides of some other elements is known to affect their capability to support hydroxyapatite formation and thus bone tissue healing but also to modify their high temperature processing parameters. In the present study, the influence of gradual substitution of SrO for CaO on the properties of the bioactive glass S53P4 was studied. Thermal analysis and hot stage microscopy were utilized to measure the thermal properties of the glasses. The in vitro bioactivity and solubility was measured by immersing the glasses in simulated body fluid for 6 h to 1 week. The formation of silica rich and hydroxyapatite layers was assessed from FTIR spectra analysis and SEM images of the glass surface. Increasing substitution of SrO for CaO decreased all characteristic temperatures and led to a slightly stronger glass network. The initial glass dissolution rate increased with SrO content. Hydroxyapatite layer was formed on all glasses but on the SrO containing glasses the layer was thinner and contained also strontium. The results suggest that substituting SrO for CaO in S53P4 glass retards the bioactivity. However, substitution greater than 10 mol% allow for precipitation of a strontium substituted hydroxyapatite layer.     

Sol–gel-derived manganese-releasing bioactive glass as a therapeutic approach for bone tissue engineering

Sol–gel processing allows the production of bioactive glasses (BG) with flexible compositions and the incorporation of different metallic ions with therapeutic benefits into the glass network. Manganese is among several previously studied therapeutically beneficial ions and has been shown to favour osteogenic differentiation, in addition to playing an important role in cell adhesion. The incorporation of Mn into bioactive glasses for tissue engineering has been previously conducted using the conventional melting route, whereas the sol–gel route has not yet been explored. Sol–gel technology has great versatility, allowing the preparation of BG with various compositions, sizes, morphologies and a large surface area that could provide improved cellular responses and enhanced bioactivity when compared to melt-derived glasses. In this context, this work developed new compositions of sol–gel bioactive glasses (on the SiO₂–P₂O₅–CaO–MnO system) and explored the effects of incorporating MnO on the structure, texture, in vitro bioactivity and cytocompatibility of these materials. Our results show that Mn-containing bioactive glasses present an amorphous character, high surface area and mesoporous structure. The formation of a hydroxycarbonate apatite (HCA) layer after immersion in simulated body fluid (SBF) revealed the high bioactivity of the glasses. Ion release evaluation indicated that the Si, Ca, P and Mn release levels could be adjusted within therapeutic limits, and cytotoxic analysis demonstrated that the ionic products of all samples generated a cell-friendly environment. Therefore, Mn incorporation into the bioactive glass network appears to be a potential strategy to develop superior materials with sustained ion release for tissue engineering.     

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。     

The use of advanced diffraction methods in the study of the structure of a bioactive calcia: silica sol-gel glass

Sol-gel derived calcium silicate glasses may be useful for the regeneration of damaged bone. The mechanism of bioactivity is as yet only partially understood but has been strongly linked to calcium dissolution from the glass matrix. In addition to the usual laboratory-based characterisation methods, we have used neutron diffraction with isotopic substitution to gain new insights into the nature of the atomic-scale calcium environment in bioactive sol-gel glasses, and have also used high energy X-ray total diffraction to probe the nature of the processes initiated when bioactive glass is immersed in vitro in simulated body fluid. The data obtained point to a complex calcium environment in which calcium is loosely bound within the glass network and may therefore be regarded as facile. Complex multi-stage dissolution and mineral growth phases were observed as a function of reaction time between 1 min and 30 days, leading eventually, via octacalcium phosphate, to the formation of a disordered hydroxyapatite (HA) layer on the glass surface. This methodology provides insight into the structure of key sites in these materials and key stages involved in their reactions, and thereby more generally into the behaviour of bone-regenerative materials that may facilitate improvements in tissue engineering applications.     

Alkali oxide containing mesoporous bioactive glasses: Synthesis,characterization and in vitro bioactivity

We report, for the first time, the synthesis of sodium oxide containing mesoporous bioactive quaternary glasses and compared with two different mesoporous ternary silicate systems by modified sol–gel process. With the aid of three different glass systems, a systematic analysis has been made on phosphorous-bearing (P-bearing) and phosphorous-free (P-free) mesoporous bioactive glasses to investigate the role of phosphorus on in vitro bioactivity of various silicate glasses with constant alkali oxide content. The combined use of multiple analytical techniques XRD, FTIR, SEM, nitrogen adsorption/desorption analysis before and after soaking in the SBF solution allowed us to establish strong correlation between composition, pore structure and bioactivity. We find that the P-bearing mesoporous glasses show the rapid hydroxycarbonate apatite (HCA) crystallization than P-free mesoporous glasses independent of calcium content. The present study reveals that the presence of phosphorous jointly with calcium in the bioactive glass system significantly enhances the rate of apatite formation as well as crystallization of apatite phase. Additionally, we find that a glass with sodium orthophosphate rich phase enhances the solubility when immersed in SBF and further accelerate the kinetics of apatite formation. The influences of the chemical composition and their superior textural properties on bioactivity are explained in terms of the unique structure of mesoporous bioactive glasses.     

Synthesis and characterisation of nanobioactive glass for biomedical applications

In recent years, bioactive materials have become important in applications such as implantation, bone regeneration, scaffold, oral implantation and antioxidant materials because of their excellent bioactivity, biocompatibility, osteoconductivity and osteoinductive properties. When exposed to simulated body fluid, bioactive glasses have the ability to bond with both hard and soft tissues through the formation of a hydroxyapatite layer. Nowadays, nanotechnology is emerging as a nascent technology in all disciplines because of its high surface-to-volume ratio and unique properties at nanoscale length. The impact of nanotechnology in biomaterials is of interest because of the enhancement in their biocompatibility and bioactivity. In this investigation, the preparation of nanobioactive glasses by using different methods (such as sol-gel, hydrothermal and sonochemical) is discussed in detail. The structural and morphological characterisation of the prepared samples was made.