软骨组织工程常用支架制备技术

随着软骨组织工程的发展,如何获得理想的支架已成为这一课题的核心热点和难点.软骨组织工程式支架要求具有特定的物理、生化特性,例如极强的生物相容性、合适的生物降解性、可控的孔径大小、足够的孔隙率队等.而这些性能的获得主要与两方面的因素有关,一是支架材料本身的影响,二是支架制备技术的选择.本综述对三维多孔支架的制备技术进行了较为全在的回顾.主要介绍了溶剂浇铸/粒子沥滤技术、相分离/冻干技术、水凝胶技术、气体发泡技术、静电纺丝技术、快速成型法.通过比较不同支架制备技术对支架结构和性质的影响,总结分析了各种技术的优缺点,同时对软骨组织工程中支架制备技术的发展趋势进行了展望.     

新型组织工程软骨支架材料及其构建技术的改进

软骨组织损伤后自身修复能力有限，组织工程学使得关节软骨的生物学替代物即人工软骨显示出美好的前景。软骨生物支架材料为组织工程的重要一环，探讨软骨生物支架材料的研究进展对构建人工软骨具有重大意义。通过对支架材料进行表面修饰、采用新型构建技术以及利用天然和合成材料的各自优势联合应用，进行多材料复合，以研制出具有生物相容性好、力学适应能力强的复合材料、仿生材料、智能材料将是近年来人工软骨生物支架材料的主要研究方向。     

关节软骨细胞外基质源性软骨组织工程取向支架的制备

背景:仿生天然软骨细胞外基质特殊的力学、结构特性和生化成分的软骨组织工程支架具有巨大的应用潜能.目的:观察仿生天然关节软骨细胞外基质的生化和结构特性,探讨关节软骨细胞外基质材料及软骨组织工程取向支架的制备方法,并对其理化性质进行检测.设计、时间及地点:组织工程材料支架制备及性能分析的体外实验,于2007-07/2008-07在解放军总医院骨科研究所完成.材料:将新鲜猪关节软骨湿法粉碎,差速离心,收集无细胞的软骨细胞外基质成分.脱氧核糖核酸酶、核糖核酸酶及碳化二亚胺、N-羟基琥珀酰亚胺均为美国Sigma公司产品.方法:对关节软骨细胞外基质材料进行组织学和形态学榆测后,用pH3.2的稀盐酸制成质量浓度为20 g/L溶液,采用定向结晶及冷冻干燥技术制成关节软骨细胞外基质源性取向支架,再采用物理化学方法交联,同时制各多孔软骨细胞外基质源性非取向支架a主要观察指标:①关节软骨细胞外基质材料的生化组成和形态.②软骨细胞外基质取向支架和非取向支架的表面特征及孔道结构.⑧取向和非取向软骨细胞外基质支架的孔隙率、吸水膨胀率、力学特性的比较.结果:收集的关节软骨细胞外基质材料中无细胞存在,纤维为纳米尺度,甲苯胺蓝、番红花O、奥新蓝染色及Ⅱ犁胶原染色阳性;制备的取向支架具有纵向排列的孔道结构,孔径100-200μ m,分布均匀,非取向支架的孔呈海绵样结构:两种支架孔隙率均≥95%,吸水膨胀率均≥96%.取向支架纵向压缩模量和拉伸模量为:(2.02±0.02),(22.10±0.67)MPa,均大于非取向支架.差异具有统计学意义(P<0.05).结论:天然关节软骨细胞外基质材料与天然关节软骨的生物力学特性相似,可满足软骨组织工程的需要,是一种比较理想的软骨组织工程支架.     

人脐带Wharton胶中间充质干细胞体外无支架组织工程软骨的构建

背景:构建组织工程软骨的方法多为自体种子细胞复合天然或合成物支架,目前多存在种子细胞来源有限、支架安全性和生物相容性、以及细胞在支架中分布不均的问题.目的:探讨人脐带Wharton胶中间充质干细胞向软骨诱导分化并体外构建无支架组织工程软骨的可行性.方法:分离培养人脐带Wharton胶中的间充质干细胞,进行流式细胞学鉴定.对软骨诱导前后的细胞进行组织学和免疫组织化学染色,对其表达的葡萄糖胺聚糖和Ⅱ型胶原进行定量研究,并应用RT-PCR检测软骨诱导前后Ⅱ型胶原和Sox-9mRNA的表达.采用密集诱导培养→离心管培养→生物反应器培养,进行体外构建无支架软骨组织.结果与结论:人脐带Wharton胶富含干细胞,流式细胞仪检测结果显示这些细胞不表达造血干细胞标志,表达CD44,CD105、CD271等间充质干细胞表面标志;HLA-ABC阳性表达,HLA-DPDQDR阴性表达.未进行软骨诱导的细胞弱表达软骨细胞标志,诱导后葡萄糖胺聚糖和Ⅱ型胶原显著增高.RT-PCR结果显示人脐带Wharton胶间充质干细胞诱导前后均表达Sox-9、Ⅱ型胶原mRNA.说明人脐带Wharton胶间充质干细胞具有前软骨细胞的特性.采用密集诱导培养结合生物反应器培养,不用支架,体外可以构建成大块组织工一[程软骨.表明人脐带Wharton胶间充质干细胞是一种良好的构建组织工程软骨的种子细胞.     

新型支架在软骨组织工程中的研究进展

关节软骨损伤在临床中司空见惯,由于关节软骨特殊的生理结构,自身修复能力较差,传统的治疗手段多效果欠佳。如何修复软骨损伤成为临床上较棘手的问题之一,也因此愈发备受临床研究者们的关注。软骨组织工程使软骨完全修复再生成为可能。合适的支架是构建组织工程化软骨的关键,为取得关节软骨最佳的修复效果,新型组织工程支架的设计不断优化,多重复合的仿生支架、纳米支架材料、水凝胶支架是当下的研究热点。该文就目前用于软骨组织工程中新型支架的材料、设计及特性等的研究进展进行综述。     

管状支架体外静态培养组织工程气管软骨

背景:前期实验已证实人气管软骨细胞在DegraPol片状支架上保持了正常的形态和活力,同时分泌软骨特有基质成分.目的:以大鼠剑突软骨细胞为种子细胞种植于DegraPol管状泡沫支架,观察新形成的工程化组织在体外静态培养条件下的组织和力学特点.设计、时间及地点:单一样本观察,于2006-12/2008-02在深圳市人民医院医学研究中心完成.材料:DegraPol管状材料为瑞士联邦理工大学聚合材料研究所提供:实验动物为2周龄体质量50～60g的SPF级SD幼鼠.方法:收集第3代幼鼠剑突软骨细胞接种于DegraPol管状支架,形成软骨细胞-支架复合物,体外静态培养6周.主要观察指标:①AO/PI荧光染色观察软骨细胞在DegraPol管状泡沫支架中的存活情况,于培养3,6周取出软骨细胞-DegraPol支架复合体,MTT法测定细胞增殖情况.②培养3,6周,应力-应变机械力学方法测定最大应变和应力的变化.③培养3,6周,扫描电镜观察软骨细胞在DegraPol支架中培养后的超微结构.结果:①AO/PI荧光染色显示软骨细胞在DegraPol支架内保持良好的活性,MTT法结果显示培养6周组A值高于培养3周组(P<0.05).②应力-应变机械力学测定结果显示,培养3周组应力值和应变值高于培养6周组(P<0.05).③扫描电镜结果显示DegraPol支架与大鼠剑突软骨细胞有良好的生物相容性,培养6周后获得更多的软骨细胞增殖和更多的细胞外基质.结论:DegraPol管状泡沫支架有良好的生物相容性并且软骨细胞在支架上保持正常活性,但由于工程化复合物的生物力学强度较差,培养条件和培养方式有待进一步改善.     

不同材料构建组织工程软骨及支架的应用

背景：组织工程技术的发展为软骨的再生和修复提供了新的途径,根据软骨自身的结构和特点,作为人工软骨的替代材料和支架材料应具有良好的生物力学性能。目的：总结运动性关节软骨损伤修复材料及其支架材料的应用进展及其生物替代材料的生物力学特征,评价目前组织工程软骨材料应用的性能及发展前景。方法：以＂组织工程;软骨组织;支架材料;生物相容性＂为关键词,应用计算机检索维普数据库和PubMed数据库中1990-01/2011-04关于组织工程软骨应用研究的文章,纳入与有关生物材料与组织工程软骨相关的文章;排除重复研究或Meta分析类文章。以24篇文献为主重点进行了讨论组织工程软骨材料的种类、性能及其应用效果和前景。结果与结论：目前关节软骨修复领域以自体软骨移植效果为最佳,骨髓基质干细胞在离体试验及动物实验中研究较多,在临床应用中较少,尚在探索阶段。支架材料的应用比较繁复,天然材料、人工合成材料以及复合材料都存在一定的不足,虽然复合材料成为研究的热点,但是某些性能并不能很好地符合支架要求,并且在机体内这些材料所带来的长期影响还不能预见,这就迫切需要新材料的出现,来更好地满足组织软骨织支架的要求,达到修复和重建的目的。     

关节软骨组织工程支架材料研究进展

组织工程学是一门交叉学科,它利用工程学和生命科学的原理,来研究和发展具有生物活性的人工替代物,用以维持、恢复或提高人体受损组织的功能。目的是利用人体活细胞在适宜的支架材料上生长成天然的组织和器官以替代人体内受损和缺失的组织和器官。支架材料的选择是组织工程学研究的焦点之一。支架材料作为人工细胞外基质,为功能细胞的停泊、生长、繁殖、     

人细胞外基质包被猪去细胞瓣膜支架构建的组织工程心脏瓣膜

背景:去细胞处理的猪主动脉瓣膜植入人体后发生了免疫排斥反应,分析引起免疫排斥反应的原因是由于猪瓣膜的细胞外基质与宿主发生接触引起了免疫激活.目的:试图将人自身的细胞外基质履盖去细胞猪瓣膜表面起到隔离猪瓣膜与宿主血液成分接触的作用.同时应用免疫组化的方法验证人细胞外基质覆盖瓣膜的效果.设计、时间及地点:观察性实验,于2008-08/2009-04在解放军第二军医大学长海医院胸心外科实验室完成.材料:新鲜猪心脏瓣膜取白上海五丰上食肉联厂,采用酶消化法将猪主动脉瓣叶行脱细胞处理.密度梯度离心法从健康志愿者骨髓中获取骨髓基质干细胞.方法:用人细胞外基质包被猪去细胞瓣膜支架来构建组织工程瓣膜,再应用前期制备的抗人细胞外基质单克隆抗体,采用免疫组织化学染色鉴定人细胞外基质在体外构建的组织工程瓣膜上的黏附情况.以未构建的去细胞猪瓣叶为对照组.主要观察指标:①组织工程瓣膜上种子细胞的黏附和生长情况.②免疫组织化学法检测人细胞外基质在瓣膜上覆盖的效果.结果:光镜下观察瓣膜表面均形成了细胞层.扫描电镜所见细胞排列欠规则,未完全覆盖去细胞瓣叶表面,可见裸露的瓣膜支架.免疫组织化学方法检测构建的瓣膜表面呈阳性反应证明有人的细胞外基质黏附,而对照组呈阴性证明了检测方法具有特异性.结论:体外构建的组织工程瓣膜上检测到有人的细胞外基质黏附.     

骨及软骨组织工程支架材料

生物降解性三维支架材料在骨组织工程制备中起着十分重要的作用,它与种子细胞共同构成组织工程的核心-三维空间复合体。目前取得较好效果的骨及软骨组织工程支架材料,主要由L-聚乳酸、聚乙醇酸及其共聚物等加工而成的纤维网状或微孔海绵状材料。     

软骨组织工程支架材料研究的现状

目的:总结和分析软骨组织工程支架材料的研究进展、现状及其发展趋势。资料来源:应用计算机检索Medline1996-01/2006-10关于软骨组织工程支架材料方面的文章。检索词“cartilagedefects,tissueengineering,scaffold”并限定文章的语言种类为English。同时利用计算机检索中国期刊全文数据库1996-01/2006-10的相关文章,限定文章语言种类为中文,检索词“组织工程、软骨损伤、支架材料”等。资料选择:对资料进行初审,纳入标准:①关于软骨组织工程材料研究的现状、研究进展及发展方向。②对具体研究的回顾调查研究。排除标准:重复性研究。资料提炼:共收集到符合上述要求的文献62篇,排除28篇重复性研究。34篇符合纳入标准。资料综合:在软骨组织工程中支架材料起着非常重要的作用,选择合适的载体是一个首先要解决的问题。在生物材料研制与开发过程中,应特别注重细胞与生物材料相互作用的研究,避免生物材料研究与种子细胞研究脱节。对材料进行生物或化学修饰的复合材料、纳米材料、仿生材料及智能材料等的研制与开发将是未来生物材料研究的重要内容。结论:选用软骨组织组织工程支架材料时,应充分考虑到无机材料、有机材料及自体骨材料的优缺点,通过表面改性提高材料的生物性能     

Investigating cellulose derived glycosaminoglycan mimetic scaffolds for cartilage tissue engineering applications

Articular cartilage has a limited capacity to heal and, currently, no treatment exists that can restore normal hyaline cartilage. Creating tissue engineering scaffolds that more closely mimic the native extracellular matrix may be an attractive approach. Glycosaminoglycans, which are present in native cartilage tissue, provide signalling and structural cues to cells. This study evaluated the use of a glycosaminoglycan mimetic, derived from cellulose, as a potential scaffold for cartilage repair applications. Fully sulfated sodium cellulose sulfate (NaCS) was initially evaluated in soluble form as an additive to cell culture media. Human mesenchymal stem cell (MSC) chondrogenesis in pellet culture was enhanced with 0.01% NaCS added to induction media as demonstrated by significantly higher gene expression for type II collagen and aggrecan. NaCS was combined with gelatine to form fibrous scaffolds using the electrospinning technique. Scaffolds were characterized for fibre morphology, overall hydrolytic stability, protein/growth factor interaction and for supporting MSC chondrogenesis in vitro. Scaffolds immersed in phosphate buffered saline for up to 56 days had no changes in swelling and no dissolution of NaCS as compared to day 0. Increasing concentrations of the model protein lysozyme and transforming growth factor‐β3 were detected on scaffolds with increasing concentrations of NaCS (p < 0.05). MSC chondrogenesis was enhanced on the scaffold with the lowest NaCS concentration as seen with the highest collagen type II production, collagen type II immunostaining, and expression of cartilage‐specific genes. These studies demonstrate the feasibility of cellulose sulfate as a scaffolding material for cartilage tissue engineering. Copyright © 2016 John Wiley & Sons, Ltd.     

Collagen scaffolds for nonviral IGF-1 gene delivery in articular cartilage tissue engineering

This study investigated the use of a type II collagen-glycosaminoglycan (CG) scaffold as a nonviral gene delivery vehicle for facilitating gene transfer to seeded adult articular chondrocytes to produce an elevated, prolonged and local expression of insulin-like growth factor (IGF)-1 for enhancing cartilage regeneration. Gene-supplemented CG (GSCG) scaffolds were synthesized by two methods: (1) soaking a pre-cross-linked CG scaffold in a plasmid solution followed by a freeze-drying process, and (2) chemically cross-linking the plasmid DNA to the scaffold. Two different plasmid solutions were also compared: (1) naked plasmid IGF-1 alone, and (2) plasmid IGF-1 with a lipid transfection reagent. Plasmid release studies revealed that cross-linking the plasmid to the CG scaffold prevented passive bolus release of plasmid and resulted in vector release controlled by scaffold degradation. In chondrocyte-seeded GSCG scaffolds, prolonged and elevated IGF-1 expression was enhanced by using the cross-linking method of plasmid incorporation along with the addition of the transfection reagent. The sustained level of IGF-1 overexpression resulted in significantly higher amounts of tissue formation, chondrocyte-like cells, GAG accumulation, and type II collagen production, compared to control scaffolds. These findings demonstrate that CG scaffolds can serve as nonviral gene delivery vehicles of microgram amounts of IGF-1 plasmid (<10 microg per scaffold) to provide a locally sustained therapeutic level of overexpressed IGF-1, resulting in enhanced cartilage formation.     

Injectable cartilage tissue engineering

Cartilage is the tissue that lines the surface of bones in articulating joints, allowing painless joint movement. Cartilage loss is an increasingly significant problem, particularly with the ageing of active baby boomers, with few efficacious treatments available at present. Tissue engineering is a field that has evolved over recent years to combat tissue loss by providing a living tissue equivalent or substitute that can mimic the properties of the lost tissue. The general strategy of tissue engineering is to place cells on a biomaterial scaffold that is designed to promote cell function and form new tissue. This review describes the status of materials that are available as injectable scaffolds for tissue engineering and the numerous cell types that can be applied to cartilage repair, including cells derived from cartilage and stem cells. The current state of injectable cartilage tissue engineering and the hurdles that remain for widespread clinical application are discussed.     

骨组织工程支架表面修饰材料的研究与进展

目的:为提高骨组织工程支架材料表面的细胞黏附性,选择最佳的骨移植材料提供理论依据。资料来源:应用计算机检索Medline1995-01/2004-07相关文章,检索词“bonesubstitutes,modified,并限定文章语言种类为English。资料选择:对36篇资料的进行初审,纳入条件:①关于立体支架材料方面的文章。②单一样本的基础研究。③临床研究。排除条件:①关于金属材料的文章。②重复研究。③综述文献。资料提炼:共收集到30篇关于支架材料表面修饰的文章,其中24篇符合上述标准。排除的6篇为重复研究和综述文献。资料综合:对24篇相关文献涉及的纤维蛋白,几丁质及其衍生物,细胞生长因子,合成材料等表面修饰材料的表面特性、局部形态和化学能等方面进行综述。结论:成骨细胞与材料的作用依赖于材料的表面特性、局部形态、表面能或化学能等。这些表面特性决定了细胞怎样吸附到材料表面、细胞的定位以及细胞的功能行为。目前应用最多的表面修饰材料是I型胶原。     

Evaluation of the potential of novel PCL-PPDX biodegradable scaffolds as support materials for cartilage tissue engineering

Cartilage is a specialized tissue represented by a group of particular cells (the chondrocytes) and an abundant extracellular matrix. Because of the reduced regenerative capacity of this tissue, cartilage injuries are often difficult to handle. Nowadays tissue engineering has emerged as a very promising discipline, and biodegradable polymeric scaffolds are widely used as tissue supports. In cartilage injuries, the use of autologous chondrocyte implantation from non-affected cartilage zones has emerged as a very interesting technique, where chondrocytes are expanded in order to obtain a greater number of cells. Nevertheless, it has been reported that chondrocytes in bidimensional cultures suffer a dedifferentiation process. The present study sought, in the first place, to standardize a novel protocol in order to obtain primary cultures of chondrocytes from newborn rabbit hyaline cartilage from the xiphoid process. Second, the potential of porous three-dimensional (3D) biodegradable polymeric matrices as support materials for chondrocytes was evaluated: a novel poly(ε-caprolactone)-poly(p-dioxanone) (PCL-PPDX) blend in a 90:10 w:w ratio and poly(ε-caprolactone) (PCL). After achieving the standardization, a typical round-shaped chondrocyte morphology and the expression of collagen type II and aggrecan, evaluated by RT-PCR, were observed. Second-passage chondrocytes adhered effectively to these scaffolds, although cell growth at 7 days in culture was significantly less in the PCL-PPDX blend. After 3 weeks of culture on PCL-PPDX or PCL, the cells expressed collagen type II. The present study demonstrates the potential, unknown until now, of PCL-PPDX blend scaffolds in the field of cartilage tissue engineering.     

Cartilage tissue engineering using resorbable scaffolds

Cartilage tissue engineering holds considerable promise for orthopaedic and reconstructive head and neck surgery. With an increasingly ageing population, the number of patients affected by arthritis and recurrent joint pain is constantly growing, along with the associated socio-economic costs. In head and neck surgery reconstructive procedures gain increasing importance in multimodal tumour therapies. These procedures require the harvesting of large amounts of donor tissue, which causes significant donor site morbidity. Therefore, in vitro-engineered cartilage may provide for a cost-effective and clinically valuable medical need. This article presents an overview of the clinical background as well as considerations for engineered cartilage in the head and neck, and provides examples of cartilage tissue engineering based on various scaffolds.     

牙髓牙本质组织工程生物支架材料的研究进展

背景：组织工程方法中选择合适的支架是关键性的步骤。目的：回顾分析牙髓牙本质组织工程中支架材料的应用研究。方法：由第一作者检索1993至2012年PubMed数据及万方数据库有关牙髓牙本质组织工程中支架材料应用研究等方面的文献。结果与结论：在牙髓牙本质组织工程中有包括天然生物、人工合成材料和复合材料在内的大量生物材料可供选择,每一种材料都有各自的生物学特点。其中胶原、聚酯、羟基磷灰石等是研究较多的支架材料。自组装多肽水凝胶是由氨基酸制成的新型支架材料,满足理想牙髓牙本质组织工程支架材料的大部分要求,是一种前景广阔的牙髓牙本质组织工程支架材料。     

3D ingrowth of bovine articular chondrocytes in biodegradable cryogel scaffolds for cartilage tissue engineering

A feasibility study was undertaken to examine the potential of biodegradable HEMA-lactate-dextran (HEMA-LLA-D)-based cryogels as scaffolds for cartilage tissue engineering. This was a preliminary in vitro study giving essential information on the biocompatibility of cryogels with cartilage cells. HEMA-lactate (HEMA-LLA) and HEMA-LLA-D were synthesized and characterized by different techniques. Cryogel scaffolds with supermacroporous structures were produced by cryogenic treatment of these macromers. Chondrocytes obtained from bovine articular cartilage were seeded onto cylindrical cryogels and cultured. The samples were examined by several microcopical techniques for cell viability and morphological analyses were performed at two culture points. Histological study of the constructs revealed the cells' growth on the surface and within the scaffolds. Confocal microscopical images demonstrated that the majority of live vs. dead cells had been attached to and integrated with the pores of the scaffold. SEM analysis showed round to oval-shaped chondrocytic cells interconnected with each other by communicating junctions. The chondrocytes rapidly proliferated in the cryogels, manifesting that they fully covered the scaffold surface after 9 days and almost filled the spaces in the pores of the scaffold after 15 days of culture. Chondrocytes secreted significant amount of extracellular matrix in the scaffolds and exhibited highly interconnective morphology. Light and transmission electron microscopy revealed groups of active cartilage cells closely apposed to the cryogel. We concluded that cryogel scaffolds could be excellent candidates for cartilage tissue regeneration with their extraordinary properties, including soft, elastic nature, highly open interconnected pore structure and very rapid, controllable swellability.