生物陶瓷作为骨组织工程支架材料的研究进展

组织工程支架材料是组织工程研究的重要内容之一.骨组织工程模拟了自体骨移植的骨形成过程,支架材料、种子细胞、生长因子构成了骨组织工程的三要素.在构建组织工程骨的过程中,自体骨髓基质干细胞作为骨种子细胞,支架材料提供细胞外基质和机械支持,生长因子能诱导骨髓基质干细胞向成骨方向发展.     

低温快速成型技术与骨组织工程支架制备

骨组织工程支架作为骨组织工程三大核心之一,在种子细胞黏附、生长、分化及骨组织血管化形成中起着重要作用。多数研究显示合适孔径及高孔隙率的骨组织工程支架有利于上述生理过程进行,而孔径及孔隙率取决于材料类型及成型工艺。低温快速成型技术作为一种新型快速成型工艺,具有可实现支架孔径的高度可控性、高孔隙率及保持材料生物学活性等优势,被迅速应用于骨组织工程支架制备研究。该文就低温快速成型工艺技术的原理、工艺设备及流程、技术优势、材料要求、成型材料特点、应用前景等作一综述。     

计算机辅助成型技术制备骨组织工程支架的研究进展

目的综述计算机辅助成型技术制备骨组织工程支架的应用和相关研究进展。方法广泛查阅近年有关计算机辅助成型技术制备骨组织工程支架的文献,并进行综述。结果近10余年来许多研究致力于计算机辅助成型技术制备骨组织工程支架。该技术包括骨支架建模和骨支架快速成型,骨支架建模方法包括医学计算机辅助设计界面法、STL界面法和反求界面法,反求界面法可以完全模拟正常骨组织,是目前最好的建模方法。快速成型包括多种方法,如熔融沉积技术、三维打印技术、选择性激光烧结技术、三维生物描绘技术、低温沉积制造技术,可以制备出包含骨骼内部结构的三维孔隙结构。结论随着支架建模和制造成型技术的不断改进,计算机辅助成型技术将成为制备骨组织工程支架的主要有效手段。     

磷酸钙生物陶瓷在骨及软骨组织工程中的应用

为修复肿瘤、创伤及病理因素引起的骨缺损,随着纳米和生物技术的发展,一系列新型的骨组织工程支架材料被制备出来。磷酸钙生物陶瓷作为一种可吸收的生物陶瓷,具有良好的骨传导性能、成骨性能及可控降解性能,在骨组织工程中日益被人们所熟知。同时,磷酸钙有较高的生物活性,对成骨细胞的黏附、增殖及分化等起着重要作用,并可以降低环境改变引起的细胞损害,是较为理想的骨替代材料。为了更好地掌握纳米生物材料的优点和指导制备新型的骨组织工程支架材料,本文对作为骨组织工程支架材料之一的磷酸钙生物陶瓷的种类、理化性质、生物活性、细胞支架的骨组织工程等进行综述,并对其研究和发展作出展望。     

骨组织工程支架材料的研究进展

寻找理想的支架材料是目前骨组织工程研究的热点之一。本文着重阐述了几种骨组织工程材料的特点及应用现状,分析各材料的优缺点,展望了骨组织工程支架材料的发展趋势。     

nHA-PLGA支架材料与兔软骨细胞体外培养的生物相容性研究

目的 研究新型多孔复合支架材料纳米羟基磷灰石(nHA)-聚乳酸羟基乙酸共聚物(PLGA)的生物相容性,探讨其作为骨组织工程支架的可行性.方法 将胎兔膝关节软骨细胞接种于制备的nHA-PLGA复合支架上,体外共同培养后采用四甲基偶氮唑蓝(MTT)法检测软骨细胞增殖活性,倒置荧光显微镜、扫描电镜观察支架材料表面和孔隙内软骨细胞黏附情况,流式细胞术检测软骨细胞周期情况.结果 实验组(A组)复合支架材料上细胞增殖活性与空白对照组(B组)相比,无统计学差异(P＞0.05);倒置荧光镜、扫描电镜观察显示A组细胞在复合支架材料表面和孔隙内大量黏附、生长,其数量随着共培养时间增加呈几何级增长;流式细胞仪检测显示A组与B组细胞周期差异无统计学意义(P＞0.05).结论 nHA-PLGA多孔复合支架生物相容性好,是一种性能良好的骨组织工程支架材料.     

静电纺丝纳米纤维在骨组织工程中的应用

静电纺丝纳米纤维技术在生物医学领域有着广泛的应用研究,其在骨组织工程应用中仍未解决的问题是同时满足材料的生物相容性、可降解性、生物活性和力学性能。骨组织工程主要构成要素是支架、细胞和生长因子。静电纺丝复合纳米纤维支架材料具有纳米级别的天然骨分级结构和天然骨的多孔结构,改进复合支架材料可促进细胞的浸润生长、干细胞分化和组织形成。本文重点探讨通过静电纺丝技术改进复合支架的性能,及其在动物实验研究方面的最新进展。     

骨组织工程相关研究新进展

目的对近年来骨组织工程相关研究的新进展进行综述。方法查阅近年来国内外骨组织工程研究的相关文献,总结其最新进展。结果近年来,骨组织工程取得了长足进步,多家单位已成功将其应用于临床,国家卫生部也制订了相关管理规范。在种子细胞领域,多采用自体成体干细胞和异体细胞,胚胎干细胞及自体体细胞来源的诱导多能干细胞成为目前的研究热点。支架材料方面,由天然提取成分构建的材料发展为人工合成的高分子材料;由单一的支架材料发展成复合材料、表面修饰材料。在组织构建方面,既往多采用细胞悬液滴入支架材料的静置接种法,生物反应器为细胞组织的体外培养提供了稳定的微环境,可满足不同组织培养所需的条件,为组织构建和体外培养提供了新选择。结论以上进步推动了骨组织工程的快速发展,不久的将来有望研制出一系列组织工程骨医疗产品造福于广大患者。     

生物打印技术的发展及其在骨组织工程中的应用

近几十年来, 骨组织工程在治疗大块骨缺损方面取得较大的进展, 其中生物打印是最重要的技术之一。3D生物打印通过分层添加不同的材料, 实现骨组织工程支架制造空间结构的精确控制, 且以水凝胶类材料作为基础将细胞植入支架中, 解决了细胞在支架内的均匀分布。然而, 大多数用于3D生物打印的生物医学材料均为静态, 不能随着身体内部环境的动态变化而改变。4D生物打印是将时间概念与3D生物打印相结合或者利用刺激响应材料在各种刺激下改变其形状的原理, 用于制造动态三维模式的生物结构, 为骨组织工程提供了前所未有的潜力。打印结构的形状记忆特性满足了个性化骨缺损修复的需要, 而功能成熟程序促进了干细胞的成骨分化。通过总结近年来国内外生物打印用于组织工程的研究, 综述了常用的3D生物打印方法、3D生物打印发展到4D生物打印技术中功能及形态转化的机制, 并且介绍了生物打印在骨组织工程中治疗骨缺损的应用以及当前的挑战和未来的展望。     

骨组织工程中种子细胞与材料黏附的有关蛋白及影响因素

骨组织工程近年的迅速发展为人们解决大段骨缺损的治疗难题提供了另一种途径。在骨组织工程研究中,细胞与支架材料的相互作用一直都是研究的重要领域,其核心是种子细胞在细胞外基质支架材料上的黏附。作为锚合依赖性细胞,成骨细胞在种植体表面的黏附、丛集是接触成骨的关键。只有当细胞与材料界面发生适当的黏附后,细胞才能进行迁移、增殖和分化。可以说,组织工程成功与否的关键之一就在于细胞在支架材料表面的黏附程度。     

Electrospun scaffolds for bone tissue engineering

Tissue engineering aims to regenerate native tissues and will represent the alternative choice of standard surgery for different kind of tissue damages. The fundamental basis of tissue engineering is the appropriate selection of scaffolds and their morphological, mechanical, chemical, and biomimetic properties, closely related to cell lines that will be seeded therein. The aim of this review is to summarize and report the innovative scientific contributions published in the field of orthopedic tissue engineering, in particular about bone tissue engineering. We have focused our attention on the electrospinning technique, as a scaffold fabrication method. Electrospun materials are being evaluated as scaffolds for bone tissue engineering, and the results of all these studies clearly indicate that they represent suitable potential substrates for cell-based technologies.     

基于陕速成型技术的可控结构多孔硅酸钙支架的制备及体外研究

目的 利用快速成型技术制备可控结构多孔硅酸钙(rapid pfototyping-calcium silicate,RP-CS)支架,并评价其特性和体外生物学表现.方法 利用间接快速成型技术,结合固态自由成型和凝胶铸模的优点.制备町控结构RP-CS支架.与采用间法制备的多孔磷酸钙(RP-tricalcium phosphate,RP-TCP)支架相对照,将其置人体外模拟体液(simulated body fluid,SBF)、体外骨髓细胞共培养进行研究.结果 所制备RP-CS支架具有相互连通的孔道结构,平均孔隙率为71%,平均轴向压缩强度为28MPa.平均孔道直径为(555.82±29.77)μm.体外SBF浸置试验发现RP-CS支架上有羟基磷灰石的沉积,说明此支架具有体外生物活性.体外细胞共培养试验表明,兔骨髓细胞可以在此支架表面贴附并分化.MTT表明共培养7 d、14 d,细胞增殖RP-CS组均明显高于RP-TCP组(P<0.05).共培养7 d时,碱性磷酸酶活性RP-CS组明显高于RP-TCP组(P<0.05),提示CS可能具有促进骨髓细胞向成骨细胞分化的能力.结论 利用快速成型技术制备的可控结构RP-CS具有良好的生物相容性,在骨组织工程领域具有广泛应用前景.     

Present status and future potential of enhancing bone healing using nanotechnology

An overview of the current state of tissue engineering material systems used in bone healing is presented. A variety of fabrication processes have been developed that have resulted in porous implant substrates that can address unresolved clinical problems. The merits of these biomaterial systems are evaluated in the context of the mechanical properties and biomedical performances most suitable for bone healing. An optimal scaffold for bone tissue engineering applications should be biocompatible and act as a 3D template for in vitro and in vivo bone growth; in addition, its degradation products should be non-toxic and easily excreted by the body. To achieve these features, scaffolds must consist of an interconnected porous network of micro- and nanoscale to allow extensive body fluid transport through the pores, which will trigger bone ingrowth, cell migration, tissue ingrowth, and eventually vascularization.     

Injectable hydrogels for cartilage and bone tissue engineering

Tissue engineering has become a promising strategy for repairing damaged cartilage and bone tissue. Among the scaffolds for tissue-engineering applications, injectable hydrogels have demonstrated great potential for use as three-dimensional cell culture scaffolds in cartilage and bone tissue engineering, owing to their high water content, similarity to the natural extracellular matrix(ECM), porous framework for cell transplantation and proliferation, minimal invasive properties, and ability to match irregular defects. In this review, we describe the selection of appropriate biomaterials and fabrication methods to prepare novel injectable hydrogels for cartilage and bone tissue engineering. In addition, the biology of cartilage and the bony ECM is also summarized. Finally, future perspectives for injectable hydrogels in cartilage and bone tissue engineering are discussed.     

可控微结构电子束熔化成形钛合金支架作为成骨细胞载体修复兔骨缺损的研究

目的 探讨可控微结构电子束熔化成形钛合金支架作为成骨细胞载体修复兔骨缺损的可行性.方法 应用电子束熔化成形技术制备支架,将成骨细胞与支架复合培养7 d后,通过扫描电镜观察细胞与材料复合情况.将培养7 d的支架/细胞复合物及单纯支架植入兔体内.72只雄性新西兰白兔均制作骨膜-骨缺损模型后随机分为4组(n=18):A组缺损处植入细胞/支架复合物,B组缺损处植入单纯支架,C组缺损处旷置,D组缺损处置入自体骨.分别在第4、8、12周取材,行大体观察、四环素荧光标记、组织学观察以及新生骨定量分析等评价新骨形成及缺损愈合情况.结果 支架与细胞体外共培养7 d后,支架表面及内部孔隙有大量细胞黏附并与材料牢固结合.第12周,新生骨组织和血管不仅在支架周围有生长,而且沿着支架的管道结构向支架内部生长并逐渐填满支架内部,新生骨组织与支架牢固结合并形成一个相互嵌合的复合体.新生骨定量分析显示:第4周,各组间两两比较,差异均无统计学意义(P＞0.05).第8周,A组分别与B、C组比较,差异均有统计学意义(P＜0.05);D组分别与B、C组比较,差异均有统计学意义(P＜0.05).第12周,组间两两比较,差异均有统计学意义(P＜0.05).结论 可控微结构电子束熔化成形钛合金支架具有良好的生物相容性,能够促进支架内新骨生成及缺损的愈合.     

Optimization of bone tissue engineering in goats: a peroperative seeding method using cryopreserved cells and localized bone formation in calcium phosphate scaffolds

BACKGROUND: Bone tissue engineering by combining cultured bone marrow stromal cells with a porous scaffold is a promising alternative for the autologous bone graft. Drawbacks of the technique include the delay necessary for cell culture and the complicated logistics. We investigated methods to bypass these drawbacks. Furthermore, we investigated the localization of bone formation inside the scaffold. METHODS: Bone marrow stromal cells from seven goats were culture expanded and cryopreserved. One week before surgery, some of the cells were thawed, cultured, and seeded on porous calcium phosphate scaffolds. The constructs were cultured for another week until implantation. The remaining cryopreserved cells were thawed just before implantation and peroperatively resuspended in plasma before combining with the scaffold. Scaffolds impregnated with fresh bone marrow, devitalized cultured constructs, and empty scaffolds served as controls. All samples were implanted in the back muscles of the goats for 9 weeks. RESULTS: Histologic examination showed minimal (<1%) bone in the empty and devitalized scaffolds, 4.2 +/- 5.1 bone area percent in the bone marrow samples, and significantly more bone in both the cultured and peroperatively seeded constructs (11.7 +/- 2.5 and 14.0 +/- 2.0%). The peripheral 350 microm of the implants contained significantly less bone. CONCLUSION: Peroperative preparation of osteogenic constructs with cryopreserved cells is feasible. These constructs yield substantially more bone than the scaffolds alone or scaffolds impregnated with fresh bone marrow. Bone deposition is much less on the scaffold periphery.     

壳聚糖-明胶网络/羟基磷灰石复合材料支架的研究--成骨细胞培养

目的　研究大鼠颅骨成骨细胞在壳聚糖 -明胶网络 /羟基磷灰石 (CS- Gel/ HA)复合材料支架上的生长情况。方法　将原代培养大鼠颅骨成骨细胞第 3代 ,密度为 1.0 1× 10 6 / m l悬液 ,种植于孔隙率分别为85 .2 0 %、90 .4 0 %和 95 .80 %的 CS- Gel/ HA支架材料中 ,利用细胞计数法检测种植后 3天 ,1、2及 3周的细胞增殖曲线 ,采用 HE和 von Kossa染色方法观察细胞生长、骨样组织形成和矿化沉积情况。结果　大鼠颅骨成骨细胞在孔隙率为 85 .2 0 %的支架中增殖较慢 ,在孔隙率为 90 .4 0 %和 95 .80 %的 CS- Gel/ HA复合材料支架上生长良好 ,增殖较快 ,周围分泌有大量细胞外基质 ,3周时局部已出现骨样组织 ,且细胞 /支架结构物有利于钙质沉积。结论　CS- Gel/ HA复合材料支架有望成为培养自体成骨细胞的材料 ,以重建新的骨组织     

Porous silk scaffolds can be used for tissue engineering annulus fibrosus

There is no optimal treatment for symptomatic degenerative disc disease which affects millions of people worldwide. One novel approach would be to form a patch or tissue replacement to repair the annulus fibrosus (AF) through which the NP herniates. As the optimal scaffold for this has not been defined the purpose of this study was to determine if porous silk scaffolds would support AF cell attachment and extracellular matrix accumulation and whether chemically decorating the scaffold with RGD peptide, which has been shown to enhance attachment for other cell types, would further improve AF cell attachment and tissue formation. Annulus fibrosus cells were isolated from bovine caudal discs and seeded into porous silk scaffolds. The percent cell attachment was quantified and the cell morphology and distribution within the scaffold was evaluated using scanning electron microscopy. The cell-seeded scaffolds were grown for up to 8 weeks and evaluated for gene expression, histological appearance and matrix accumulation. AF cells attach to porous silk scaffolds, proliferate and synthesize and accumulate extracellular matrix as demonstrated biochemically and histologically. Coupling the silk scaffold with RGD-peptides did not enhance cell attachment nor tissue formation but did affect cell morphology. As well, the cells had higher levels of type II collagen and aggrecan gene expression when compared to cells grown on the non-modified scaffold, a feature more in keeping with cells of the inner annulus. Porous silk is an appropriate scaffold on which to grow AF cells. Coupling RGD peptide to the scaffold appears to influence AF cell phenotype suggesting that it may be possible to select an appropriate scaffold that favours inner annulus versus outer annulus differentiation which will be important for tissue engineering an intervertebral disc.     

Design and fabrication of three-dimensional scaffolds for tissue engineering of human heart valves

We developed a new fabrication technique for 3-dimensional scaffolds for tissue engineering of human heart valve tissue. A human aortic homograft was scanned with an X-ray computer tomograph. The data derived from the X-ray computed tomogram were processed by a computer-aided design program to reconstruct a human heart valve 3-dimensionally. Based on this stereolithographic model, a silicone valve model resembling a human aortic valve was generated. By taking advantage of the thermoplastic properties of polyglycolic acid as scaffold material, we molded a 3-dimensional scaffold for tissue engineering of human heart valves. The valve scaffold showed a deviation of only +/-3-4% in height, length and inner diameter compared with the homograft. The newly developed technique allows fabricating custom-made, patient-specific polymeric cardiovascular scaffolds for tissue engineering without requiring any suture materials.