γ射线辐照交联PVA水凝胶关节软骨修复材料 的结构与性能研究

目的 研究制备工艺对γ射线辐照交联PVA水凝胶关节软骨修复材料的结构与摩擦学性能的影响,为其在关节软骨损伤修复提供理论基础。方法 采用冷冻解冻和辐照交联相结合的方法制备聚乙烯醇(PVA)水凝胶,研究其微观形貌、含水量及与自然软骨配副的摩擦学性能。结果 (1)微观结构的观察表明,制备的PVA水凝胶具有三维多孔网络结构,辐照交联使得网络结构更加致密和完善;(2) 水凝胶的含水量随着辐照剂量和PVA浓度的增加而减小;(3) 在往复式销-盘摩擦磨损试验机上研究本水凝胶材料与自然关节软骨配副时的摩擦学性能,结果表明,摩擦的起始阶段,双相润滑机制其主导作用,载荷主要由水凝胶中的液体相所承担,摩擦系数较小,随着载荷作用时间的延长,固体相所承受载荷的比例相对增高,摩擦系数渐渐增大且趋于稳定,润滑机制转为边界润滑。摩擦系数随着辐照剂量和PVA浓度的增加而减小。     

聚乙烯醇/羟基磷灰石复合水凝胶软骨植入材料的研究

研究了用于人工关节软骨假体的聚乙烯醇水凝胶和羟基磷灰石复合材料的结构与性能，系统讨论了含水量、羟基磷灰石含量等对其拉伸强度，压缩强度，黏弹性、润滑性等生物力学性能的影响，观察和比较了复合材料的徽观形貌。研究表明羟基磷灰石在聚乙烯醇水凝胶中分散均匀，良好相容，使复合材料的力学强度和润滑性能提高。     

生物活性玻璃/壳聚糖/羟基磷灰石复合骨修复材料制备及细胞相容性研究

目的设计一种生物活性玻璃/壳聚糖/羟基磷灰石(BG/HA/CS)复合材料的骨组织工程支架,并对其理化性能和细胞相容性进行检测。方法不同比例的BG/HA/CS混合液用冷冻干燥法制备成支架。通过计算支架孔隙率;扫描电镜、X线衍射和傅立叶红外光谱分析其微观形貌和组成;采用材料试验机进行支架的机械性能检测,并评价生物活性玻璃的加入对支架的影响。将第3代兔骨髓间充质干细胞接种于支架上,使用扫描电镜检测支架对其粘附作用,采用MTT法检测细胞在支架上增殖,并评价生物活性玻璃的加入对支架的细胞相容性影响。结果合成的BG/CS/HA支架与模具拥有同样的大小及几何形状,具有相互贯通的多孔结构,未见生物活性玻璃聚集,孔隙率最高可达86.96%,孔径大小合适(100~300um),最大压缩强度为(1.95±0.13)Mpa。X射线衍射图可以看到特征性的BG衍射峰;傅立叶变换红外光谱可见特征的BG吸收峰,这表明材料内有明确的BG;第3代兔骨髓间充质干细胞在支架上共培养1天后,细胞在支架表面粘附。部分细胞伸展,并伸出伪足。共培养5天后,可见细胞数目增多,团聚,细胞表面可见微绒毛,细胞已开始向材料内部迁移。采用MTT法测量骨髓间充质干细胞在支架上的增殖情况可以看出骨髓间充质干细胞在BG/CS/HA支架上表现出了明显的增殖。结论采用溶液共混、冷冻干燥法可以制备出BG/CS/HA支架;支架具有良好的孔隙率,较好的机械强度,良好的组织相容性,可用于骨组织工程。     

注射型纳米羟基磷灰石/聚酰胺生物活性骨修复材料的研究

利用羟基磷灰石纳米晶体与聚酰胺66复合，构成新型生物活性骨修复材料，探讨用于不规则骨缺损修复的注射型纳米复合人工骨的生物学特性及骨组织修复能力。对该材料进行X射线衍射分析、凝结时间、凝结强度等研究及动物实验研究，评价该材料的组织相容性和缺损骨组织的修复能力。结果表明该材料的X射线衍射谱与羟基磷灰石／聚酰胺复合材料的X射线衍射谱相同；液固比为0．5时复合材料易于注射；在生理盐水或血液中的凝固时间为25～30min；在生理盐水中固化48h后，抗压强度为37MPa。植入后牙槽嵴表面软组织愈合良好，实验侧牙槽嵴修复高度明显大于对照侧；组织形态学观察，4周时材料周围未见有成骨迹象，16周时材料被包裹并在与其相连的区域出现成骨早期的片状结缔组织。研究证实，以一定的复合比例构成的纳米羟基磷灰石／聚酰胺66复合材料组织相容性良好，可以注射方式实现对不规则骨缺损的修复。     

可注射生物降解型复合淀粉水凝胶修复关节骨-软骨缺损的应用研究

目的 开发一种可注射和生物降解型的水凝胶,并研究该水凝胶对软骨细胞增殖和功能表达的影响,以及在大鼠膝关节骨-软骨缺损模型中的修复效果。方法 以硅酸钙溶液和淀粉为主要原料加入添加剂后制备复合淀粉水凝胶,通过流变学测试、注射器推出实验和体外浸泡实验对其流变学性能、可注射性和降解性能进行表征。分离提取幼年大鼠膝关节软骨细胞并与材料浸提液进行共培养,通过CCK-8细胞增殖测试和细胞Live/Dead染色方法测定细胞毒性和活性,并通过PCR定量测试成软骨相关基因的表达量。构建大鼠膝关节骨-软骨缺损模型,通过局部注射复合淀粉水凝胶进行干预,在2周、4周和6周取大鼠膝关节标本行宏观、组织学染色评估和分析。结果 复合淀粉水凝胶具有介于固态和液态之间的流变学特征,在15 N外力下可从22 G针头中稳定推出,在PBS溶液中浸泡10 d后质量损失率为38wt.%。复合淀粉水凝胶浸提液对软骨细胞增殖无抑制作用,并提高了其Ⅱ型胶原基因和SOX-9基因的表达量。动物实验显示治疗4周和6周后复合淀粉水凝胶组的组织学评分高于未治疗组,组织学染色也显示该水凝胶可促进软骨细胞外基质合成。结论 复合淀粉水凝胶具有良好的可注射性、可降解性和生物相容性,可以提升软骨细胞Ⅱ型胶原基因和SOX-9基因的表达量,并可在体内促进骨-软骨缺损修复。     

应用天然水凝胶修复关节软骨损伤的研究进展

由创伤或骨关节炎造成的软骨损伤是常见的关节疾病类型,是现代社会严重的经济负担,对患者造成极大的痛苦。因为软骨中无神经、血管和淋巴组织,且软骨细胞迁移能力差,祖细胞数量少,导致软骨缺损的自愈能力受到很大限制。水凝胶具有诸多特性,如高吸水性能、生物降解性、可控的孔隙率及生物相容性,具有用作关节软骨替代物所需的仿生性能,已发展成为材料科学中适合应用于软骨再生的支架生物材料之一。本综述总结了用于关节软骨修复水凝胶及动物模型。由于受当前技术的局限,人们仍然难以克服诸如血管生成和机械性能不足等问题,本综述的主要目的是回顾应用天然水凝胶用于软骨损伤的进展,希望为临床治疗关节软骨损伤提供新的思路。     

以色列开发出软骨修复水凝胶

以色列瑞珍提斯生物材料公司开发出一种软骨修复水凝胶。这种水凝胶由聚乙烯醇和一定比例的纤维蛋白原构成，是一种可生物降解合成材料．将其注入软骨受伤部位后能根据需要凝化成所需形状．通过释放出的纤维蛋白原诱使软骨细胞再生并与周围组织自然融合。     

介孔-大孔生物活性玻璃的合成及其生物活性**◆

背景：多孔生物活性玻璃材料具有较大的比表面积、孔隙率以及贯通的孔道结构,可以加速羟基磷灰石沉积的动力学速率从而提高材料诱导形成新骨的能力。 目的：利用有机酸替代无机酸来合成新型介孔-大孔生物活性玻璃。 方法：将柠檬酸和P123加入到无水乙醇中,在室温下搅拌2 h至溶液澄清。依次加入正硅酸乙酯、四水硝酸钙和三磷酸乙酯,继续搅拌24 h。将所得溶胶倒入培养皿中,在室温下放置7 d,之后高温下烧结除去有机物模板。 结果与结论：①利用有机酸所制备的材料具有大孔结构,拥有较大的比表面积、孔隙率和孔径。②合成的介孔-大孔生物活性玻璃在人工模拟体液中可以诱导形成含碳羟基磷灰石,表现出了较好的生物活性,有望成为一种具有发展前景的骨缺损修复替代材料。     

聚乙烯醇/羟基磷灰石复合水凝胶修复膝关节软骨缺损的组织相容性

背景：将羟基磷灰石与聚乙烯醇水凝胶复合之后应用于软骨缺损修复中,可在软骨连接部位产生良好的生物活性,有效促进骨细胞的生长,提高植入材料的稳定性和生物活性。 目的：观察聚乙烯醇/羟基磷灰石复合水凝胶修复兔膝关节软骨缺损的组织相容性。 方法：取20只新西兰大白兔,随机分为空白对照组(n=6)与实验组(n=14),构建单侧膝关节软骨缺损模型,空白对照组不予以修复,实验组予以聚乙烯醇/羟基磷灰石复合水凝胶修复。术后4,8,12周获取膝关节标本进行大体观察及组织学观察。 结果与结论：空白对照组关节软骨面在术后12周内始终未得到修复,软骨下缺损存在肉芽组织充填现象,组织学也未见明显修复。实验组术后4周可见聚乙烯醇/羟基磷灰石复合水凝胶填充于缺损处,与周围软骨组织之间连接紧密,且存在清晰的界限,未出现细胞长入情况;至12周时,聚乙烯醇/羟基磷灰石复合水凝胶呈白色、半透明状,表面平坦,与周围软骨组织之间存在清晰界限,两者交界面存在软骨细胞大量增殖现象,与周围组织发生紧密结合,二者之间无间隙,底部与软骨下骨紧密连接,并存在骨样组织长入。表明聚乙烯醇羟基磷灰石复合水凝胶修复兔膝关节软骨缺损具有良好的组织相容性。 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

丝素蛋白/生物活性玻璃复合纤维膜的制备及性能表征

背景:在构建具有生物功能的引导骨再生膜时,单一材料因功能不足而无法满足临床上的需要,因此将多种材料复合已成为目前组织修复工程的一种趋势。目的:通过静电纺丝技术制备丝素蛋白/生物活性玻璃复合纤维膜,表征其理化性能和体外生物相容性。方法:将0.8 g丝素蛋白溶解于10 mL六氟异丙醇中制备静电纺丝溶液,利用静电纺丝技术制备丝素蛋白纳米纤维膜(记为SF纤维膜);将0.1,0.3,0.5,0.8 g的生物活性玻璃分别加入静电纺丝溶液中,利用静电纺丝技术制备丝素蛋白/生物活性玻璃复合纤维膜(依次记为SF/1BG、SF/3BG、SF/5BG、SF/8BG纤维膜)。表征5组纤维膜的理化性能及生物相容性。结果与结论:①扫描电镜下可见5组纤维表面光滑、连续且均匀,无串珠样结构,丝纤维之间无明显粘连,均表现出随机排布的无序多孔结构,添加生物活性玻璃后纤维膜的纤维直径减小。傅里叶红外光谱与X射线衍射检测显示,纤维膜中丝素蛋白与生物活性玻璃的化学结构稳定。SF、SF/1BG、SF/3BG、SF/5BG、SF/8BG纤维膜表面的水接触角分别为105.02°,72.58°,78.13°,79.35°,72.50°。②将骨髓间充质干细胞分别接种于5组纤维膜上,CCK-8检测显示相较于SF、SF/8BG纤维膜,SF/1BG、SF/3BG、SF/5BG纤维膜可促进骨髓间充质干细胞的增殖;活/死细胞染色显示5组纤维膜表面的细胞活力较好,其中SF/5BG纤维膜表面的细胞数量更多、分布更均匀;罗丹明-鬼笔环肽染色与扫描电镜观察显示相较于SF纤维膜,SF/5BG纤维膜更有利于骨髓间充质干细胞的黏附。将骨髓间充质干细胞分别接种于5组纤维膜上进行成骨诱导分化,SF/3BG、SF/5BG组碱性磷酸酶活性高于其他3组(P<0.05,P<0.01,P<0.001);茜素红染色显示,添加生物活性玻璃后纤维膜的钙结节形成增加,并且以SF/5BG组钙结节形成最多。③结果表明,丝素蛋白/生物活性玻璃复合纤维膜具有良好的生物安全性和生物相容性。     

Chondrocyte-seeded hydroxyapatite for repair of large articular cartilage defects. A pilot study in the goat

The aim of this study was to evaluate the potential for restoration of a large cartilage defect in the goat knee with hydroxyapatite (HA) loaded with chondrocytes. Isolated chondrocytes were suspended in fibrin glue, seeded on top of the HA, and then the composite graft was implanted in the defect. After transplantation, cell behaviour, newly synthesised matrix and the HA–glue interface were assessed histologically after 2, 4, 12, 26 and 52 weeks. Special attention was paid to the incorporation process of HA in the subchondral bone and interactions between this biomaterial and the fibrin-glue–chondrocyte suspension.

Chondrocytes in the glue proved to survive the transplantation procedure and produced new metachromatically stained matrix two weeks after implantation. The glue–cell suspension had penetrated the superficial porous structure of the HA. Four weeks after surgery, islands of hyaline-like cartilage were observed at the HA–glue interface. A layer of fibrous tissue was formed surrounding the HA graft, resulting in a relatively instable fixation of the HA in the defect. This instability of the graft in the defect, possibly together with early weight bearing, resulted in a gradual loss of the newly formed hyaline cartilage-like repair tissue. Progressive resorption of the HA occurred without any sign of active bone remodelling from the host site. One year after surgery part of the defect which extended down to the cancellous bone had been predominantly restored with newly formed lamellar bone. Only small HA remnants were still present at the bottom of the original defect. Resurfacing of the joint had occurred with fibrocartilaginous repair tissue.

The absence of adequate fixation capacity of the HA near the joint space resulted in a relative instability of the graft with progressive resorption. Therefore, HA is not a suitable biomaterial to facilitate the repair of large articular cartilage defects.     

Self-reinforced composites of bioabsorbable polymer and bioactive glass with different bioactive glass contents. Part II: In vitro degradation

The in vitro degradation behavior of self-reinforced bioactive glass-containing composites was investigated comparatively with plain self-reinforced matrix polymer. The materials used were spherical bioactive glass 13-93 particles, with a particle size distribution of 50-125 microm, as a filler material and bioabsorbable poly-L,DL-lactide 70/30 as a matrix material. The composites containing 0, 20, 30, 40 and 50 wt.% of bioactive glass were manufactured using twin-screw extruder followed by self-reinforcing. The samples studied were characterized determining the changes in mechanical properties, thermal properties, molecular weight, mass loss and water absorption in phosphate-buffered saline at 37 degrees C for up to 104 weeks. The results showed that the bioactive glass addition modified the degradation kinetics and material morphology of the matrix material. It was concluded that the optimal bioactive glass content depends on the applications of the composites. The results of this study could be used as a guideline when estimating the best filler content of other self-reinforced osteoconductive filler containing composites which are manufactured in a similar way.     

Mechanical properties of bioactive glass 9-93 fibres

Fibres were manufactured from bioactive glass 9-93 by melt spinning. The manufactured fibres were further characterized by measuring their mechanical properties. The tensile strength of 9-93 glass fibres with a diameter between 20 microm and 140 microm and the flexural strength of glass fibres with a diameter of 500-800 microm were measured. The tensile strength of fibres was highly dependent on fibre diameter. Thin fibres possessed the highest strength, 1,625 MPa, compared to the strength of the thickest fibres tested, which was 617 MPa. The flexural strength of glass 9-93 fibres was approximately 1,000 MPa and the flexural modulus 64 GPa. The Weibull modulus for tensile and flexural strength values was rather low, at about 2-4.     

新型介孔二氧化硅纳米微球/羟基磷灰石/生物玻璃复合生物涂层的体外理化特性

目的本实验设计制备了介孔硅纳米微球(mesoporous silica nanoparticulate,MSN)/羟基磷灰石(hydroxyapatite,HA)/生物玻璃(bioactive glass,BG)复合生物涂层。并对其加载唑来膦酸(Zoledronic acid,ZOL)后的体外药物释放特性进行了研究。方法通过扫描电镜、透射电镜及能谱仪等方法观察H/M涂层表征。通过高效液相色谱法进行HA/MSN/BG、HA/MSN及HA生物涂层体外ZOL加载及释放的比较。结果通过扫描电镜观察HA/MSN涂层,发现其具有二氧化硅微球组成的多孔结构。体外药物实验中H/M比HA载药量大更且与初始药物浓度相关,并具有药物缓释的特性,涂布BG后缓释效应更加明显。结论 H/M/B因其具有载药量大及药物缓释特性,为生物涂层内固定物在骨折愈合上的应用提供了新技术。     

Tissue-engineered cartilage with inducible and tunable immunomodulatory properties

The pathogenesis of osteoarthritis is mediated in part by inflammatory cytokines including interleukin-1 (IL-1), which promote degradation of articular cartilage and prevent human mesenchymal stem cell (MSC) chondrogenesis. In this study, we combined gene therapy and functional tissue engineering to develop engineered cartilage with immunomodulatory properties that allow chondrogenesis in the presence of pathologic levels of IL-1 by inducing overexpression of IL-1 receptor antagonist (IL-1Ra) in MSCs via scaffold-mediated lentiviral gene delivery. A doxycycline-inducible vector was used to transduce MSCs in monolayer or within 3D woven PCL scaffolds to enable tunable IL-1Ra production. In the presence of IL-1, IL-1Ra-expressing engineered cartilage produced cartilage-specific extracellular matrix, while resisting IL-1-induced upregulation of matrix metalloproteinases and maintaining mechanical properties similar to native articular cartilage. The ability of functional engineered cartilage to deliver tunable anti-inflammatory cytokines to the joint may enhance the long-term success of therapies for cartilage injuries or osteoarthritis.     

人膝关节软骨与聚乙烯醇水凝胶人工软骨压缩实验比较研究

目的 比较人膝关节软骨和聚乙烯醇水凝胶（PVA-H）人工软骨的生物力学性能 方法 使用人膝关节软骨和PVA-H人工软骨进行轴向压缩试验,分别进行压缩应力应变、应力松弛和蠕变实验,得到关节软骨和PVA-H人工软骨的应力应变关系。结果 实验中人关节软骨和PVA-H的力学性能有差异,人关节软骨压缩模量大于PVA-H人工软骨,人关节软骨的压缩模量为（3.6492±0.6199）Mpa,PVA-H的压缩模量为（1.5951±0.1469）Mpa。结论 软骨和PVA-H人工软骨的生物力学性能具有一定差异,试验结果对人工软骨的进一步改进具有指导意义。     

硼酸盐生物玻璃支架的制备与性能*

目的考察本实验室制备的类人体小梁骨结构的硼酸盐D-Alk-2B生物玻璃支架的体外生物降解性和生物活性、机械性能、生物相容性以及植入体内时的骨修复性能。方法①将D-Alk-2B支架浸泡于0.02M K2HPO4溶液中,考察生物玻璃支架的失重、抗压强度,浸泡液的pH随浸泡时间的变化。②将MLO-A5细胞种植于D-Alk-2B支架,经不同时间的培养,对支架的细胞成活率、碱性磷酸酶活性以及粘附细胞性能进行测试。③将D-Alk-2B支架植入大鼠皮下肌肉内,评估其骨修复性能。结果随着浸泡过程的延长,D-Alk-2B支架会逐渐降解并转化为羟基磷灰石而失重,支架的抗压强度也逐渐下降,而浸泡液的pH逐渐升高。细胞实验显示,支架能支持MLO-A5细胞分化和增殖,对碱性磷酸酶有很好的活性,能将MLO-A5细胞粘附其上。支架植入大鼠皮下肌肉,能支持软组织长入其中。结论制备的硼酸盐D-Alk-2B生物玻璃支架具有优异的生物相容性、生物活性和生物降解性,并具有骨传导和骨诱导性能,是一种前景广泛的临床应用的新型骨修复材料。     

Porous and strong bioactive glass (13-93) scaffolds prepared by unidirectional freezing of camphene-based suspensions

Scaffolds of 13-93 bioactive glass (6Na₂O, 12K₂O, 5MgO, 20CaO, 4P₂O₅, 53SiO₂; wt.%) with an oriented pore architecture were formed by unidirectional freezing of camphene-based suspensions, followed by thermal annealing of the frozen constructs to grow the camphene crystals. After sublimation of the camphene, the constructs were sintered (1 h at 700 °C) to produce a dense glass phase with oriented macropores. The objective of this work was to study how constant freezing rates (1-7 °C min⁻¹) during the freezing step influenced the pore orientation and mechanical response of the scaffolds. When compared to scaffolds prepared by freezing the suspensions on a substrate kept at a constant temperature of 3 °C (time-dependent freezing rate), higher freezing rates resulted in better pore orientation, a more homogeneous microstructure and a marked improvement in the mechanical response of the scaffolds in compression. Scaffolds fabricated using a constant freezing rate of 7 °C min⁻¹ (porosity = 50 ± 4%; average pore diameter = 100 μm), had a compressive strength of 47 ± 5 MPa and an elastic modulus of 11 ± 3 GPa (in the orientation direction). In comparison, scaffolds prepared by freezing on the constant-temperature substrate had strength and modulus values of 35 ± 11 MPa and 8 ± 3 GPa, respectively. These oriented bioactive glass scaffolds prepared by the constant freezing rate route could potentially be used for the repair of defects in load-bearing bones, such as segmental defects in the long bones.     

Modulation of chondrocyte functions and stiffness-dependent cartilage repair using an injectable enzymatically crosslinked hydrogel with tunable mechanical properties

We developed an injectable hydrogel system to evaluate the effect of hydrogel stiffness on chondrocyte cellular functions in a three-dimensional (3D) environment and its subsequent influence on ectopic cartilage formation and early-stage osteochondral defect repair in a rabbit model. The hydrogels, composed of gelatin-hydroxyphenylpropionic acid (Gtn-HPA) conjugate, were formed using oxidative coupling of HPA moieties catalyzed by hydrogen peroxide (H₂O₂) and horseradish peroxidase (HRP). The storage modulus (G′) of the hydrogels, which was tunable by changing the H₂O₂ and Gtn-HPA concentrations, ranged from 570 Pa to 2750 Pa. It was found that the cellular functions of chondrocytes encapsulated in hydrogels, including cell proliferation, biosynthesis of collagen and sulfated glycosaminoglycans (sGAG), as well as gene expression of type I (Col-I) and type II collagen (Col-II), were strongly affected by the stiffness of the hydrogels. Of note, chondrocytes cultured within the Gtn-HPA hydrogel of medium stiffness (G′ = 1000 Pa) produced highest level of sGAG production, as well as highest ratio of Col-II to Col-I gene expression among the Gtn-HPA hydrogels of different stiffness. Consistent with the results from in vitro and in vivo ectopic cartilage formation, osteochondral defect repair in a rabbit model showed stiffness-dependent tissue repair, with defects implanted with chondrocytes in hydrogels of medium stiffness having markedly more hyaline cartilage formation, smoother surface and better integration with adjacent cartilage, compared to defects treated with hydrogels of low or high stiffness. These results suggest that the tunable stiffness of Gtn-HPA hydrogels modulates chondrocyte cellular functions, and has a dramatic impact on cartilage tissue histogenesis and repair.