力学性能可控的甲基丙烯酸化明胶（GelMA）人工软骨性能及软骨/骨表界面结合研究

目的 探寻优化骨表面力学匹配的软骨修复材料,并探讨软骨修复材料与骨结合的表界面性能,为软骨修复材料的设计及制备提供依据。方法 以明胶和甲基丙烯酸酐为原料,在明胶分子中引入双键结构,使用紫外光交联的方式制备甲基丙烯酸化明胶（GelMA）水凝胶。运用扫描电子显微镜、万能力学试验机分析水凝胶的形貌、孔径大小和力学性能;体外降解实验、体外拉伸实验评估水凝胶的降解和拉伸特性;黏附能力定性实验、三维立体光学显微镜和扫描电子显微镜评估水凝胶的黏附能力;细胞增殖测试和Live/Dead染色测定细胞活性和毒性。探讨了不同紫外光照时间下GelMA水凝胶的理化性能及软骨/骨材料结合的表界面结合性能,对性能适宜的修复材料进行了配比、力学优化。结果 紫外光照（UV）交联时间为1 min时水凝胶孔隙最大（110.25±6.51）μm,孔隙率高达（45.24±2.78）%;12 h时水凝胶的平衡溶胀比达（148.43±3.84）%;28 d失重率为（17.40±2.38）wt%;水凝胶的拉伸性能随紫外光照时间延长而逐渐增加;GelMA水凝胶对骨髓间充质干细胞增殖无明显抑制作用;水凝胶软骨修复材料与骨的结合良好,可黏附于仿生骨材料表面。结论 紫外光照交联时间1 min时GelMA水凝胶的吸水速率和平衡溶胀比最佳,降解速快,拉伸性能与天然软骨结构类似,具有良好的生物相容性,与骨修复材料力学匹配,该力学性能可控的GelMA水凝胶软骨修复材料为软骨/骨的连接及性能匹配提供了依据。     

矿化胶原改性骨水泥的制备及生物力学测定

目的 基于矿化胶原（MC）对聚甲基丙烯酸甲酯（PMMA）进行改性,提高其在骨修复领域应用的可行性。方法 将不同粒径MC（＜200 μm、200 ～ 300 μm、300 ～ 400 μm、400 ～ 500 μm）按照5 wt%、10 wt%、15 wt%、20 wt%的含量加入到PMMA骨水泥,制备不同粒径及含量的复合骨水泥。通过工作特性、抗压强度、抗弯强度、压缩模量、弹性模量测试,评估MC/PMMA复合骨水泥的生物力学性能,确定最佳性能的复合骨水泥比例。结果 复合骨水泥混合时间30 s,等待时间2 ～ 5 min,工作时间5 ～ 12 min,固化时间10 ～ 20 min;不同粒径MC（＜200 μm、200 ～ 300 μm、300 ～ 400 μm、400 ～ 500 μm）复合骨水泥,在不同含量（5 wt%、10 wt%、15 wt%、20 wt%）下其抗压强度均可保持在70 MPa以上,对PMMA骨水泥的抗压强度影响不大。含量15 wt%、粒径300 ～ 400 μm MC/PMMA复合骨水泥的抗压强度90 MPa,抗弯强度50 MPa,压缩模量1.2 GPa,弹性模量较Osteopal V和Mendec Spine骨水泥明显降低,且与人体松质骨的弹性模量相匹配。结论 MC在保持PMMA机械强度的同时,可降低其弹性模量,含量15 wt%、粒径300 ～ 400 μm MC/PMMA骨水泥的工作特性、抗压和抗弯强度、弹性模量符合国际标准和临床使用要求。     

新型可吸收骨蜡的临床前动物实验研究

目的 通过动物实验了解新型可吸收骨蜡的降解周期,并研究可吸收骨蜡与骨组织的生物相容性。方法 采用18只试验羊进行骨植入试验。每只羊的6节胸骨分别作为独立的植入位点,随机选择各2个位点分别使用实验品可吸收骨蜡（实验组）或对照品强生骨蜡（对照组）止血,剩余2个位点作为空白（空白组）。术后2、6、12周各随机处死6只试验羊,取胸骨进行HE切片,进行组织学评价和材料降解情况分析。采用20只小鼠分别通过尾静脉注射和腹腔注射样品浸提液和对照观察小鼠的毒性症状。采用6只兔子通过皮内注射样品浸提液和对照观察各注射部位的红斑和水肿的组织反应。结果 实验组与空白组相比,实验品植入胸骨损伤表面2、6、12周,显示为无刺激;对照组与实验组相比,植入6、12周,显示为中度刺激。与对照品相比,实验品的组织学反应更加轻微。可吸收骨蜡降解过程中未见纤维组织包囊,新骨生长明显,至12周时,可吸收骨蜡基本降解完全,新骨连接两断端,骨损伤已得到修复。在急性毒性实验中,各组小鼠体重均稳步增长;在刺激试验中,可吸收骨蜡生理盐水的积分为0,玉米油的积分均为0.11。结论 新型可吸收骨蜡至植入12周时,已基本降解完全。该新型可吸收骨蜡是一种安全、无毒性、可用于骨创面止血的材料。     

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。     

可注射骨修复材料结合骨碎补总黄酮修复大鼠颅骨缺损

背景：自体髂骨移植一直被认为是骨缺损修复的“金标准”,但其来源有限。 目的：验证应用可注射骨修复材料结合骨碎补总黄酮修复大鼠颅骨缺损的效果。 方法：80只雄性SD大鼠建立双侧颅骨缺损模型,随机分为3组：骨修复材料+骨碎补总黄酮组采用可注射骨修复材料结合骨碎补总黄酮灌胃修复大鼠颅骨缺损;骨修复材料+去离子水组采用可注射骨修复材料结合去离子水灌胃修复大鼠颅骨缺损;羟基磷灰石+去离子水组采用羟基磷灰石结合去离子水灌胃修复大鼠颅骨缺损,1次/d,持续8周。于建模后2,4,8周取颅骨标本进行苏木精-伊红染色和Masson染色组织学观察。 结果与结论：羟基磷灰石组新骨形成和材料降解速度较慢;可注射骨修复材料组新骨形成和材料降解较羟基磷灰石组快,利于血管及纤维组织长入;骨碎补总黄酮灌胃可以促进血管及纤维组织长入材料,促进成骨。与羟基磷灰石相比,可注射骨修复材料结合骨碎补总黄酮修复大鼠颅骨缺损,可促进新骨形成,缩短骨缺损修复时间。     

可塑型生物活性骨修复材料的制备及性能表征

背景：国外研制的可注射性硫酸钙骨替代材料具有操作简便、生物相容性好、能够注射入骨缺损处、原位固化、适应骨缺损进行塑形等优点,但价格昂贵。 目的：研究以α-半水硫酸钙为主要成分可塑型骨修复材料的最佳制备参数,并对其性能进行研究和表征。 方法：使用汽热法制备粉末,将α-半水硫酸钙粉末与透明质酸钠固化液分别按液固比0.2,0.25,0.3,0.35,0.4 mL/g混合,制备可注射人工骨材料,检测其注射性能、凝固时间和抗压强度;根据检测结果选择最佳液固比0.3 mL/g,在α-半水硫酸钙粉末中分别加入质量分数为1%,2%,3%的二水硫酸钙粉末,制备可注射人工骨材料,检测其注射性能、凝固时间和抗压强度,同时检测可注射骨材料的生物安全性。将液固比为     0.3 mL/g并加入2%二水硫酸钙制备的可注射人工骨材料植入巴马小型猪胸骨缺损模型,植入后8,16,24周进行组织学观察。 结果与结论：α-半水硫酸钙粉末与透明质酸钠固化液液固比为0.3 mL/g,加入质量分数2%二水硫酸钙粉末制备的可注射人工骨材料,初凝时间为4.0-5.0 min,终凝时间为8.0-9.0 min,抗压强度(8.93±0.23) MPa,具备良好的注射性能,符合临床要求的凝固时间及作为非负重骨缺损修复要求的抗压强度,并具有良好的生物安全性。动物植入实验表明可注射人工骨材料通过自身降解,可为新生骨的爬行替代提供空间,具有一定的成骨活性。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     

新短肽P17-骨形态发生蛋白2/胶原基质矿化磷灰石材料生物活性的评价

文题释义：胶原基质矿化磷灰石：具有良好的生物相容性,不产生排斥反应,降解速度与成骨的速度相适应,其降解不会影响周围环境的pH值。该材料在微米尺度上具有互联孔洞结构,孔隙尺寸为100-500 µm,孔隙率为70%-90%,结构和成分与自体骨相似,能够更好的诱导自体骨生长,具有良好的骨修复作用,其机械耐受性、可塑性、强度接近松质骨。 新短肽P17-骨形态发生蛋白2：通过FMOC/tBu固相多肽合成法合成的具有17个氨基酸的新型活性短肽中包含磷酸化的丝氨酸及天冬氨酸,能够极好地模拟天然骨基质的促发及指导矿化的功能,在局部形成偏酸环境,促进局部的钙磷沉积、成核和生物自组装矿化。短链多肽活性位点能充分暴露并与细胞表面受体结合,生物活性更强。 背景：胶原基质矿化磷灰石材料具有仿生的化学组成及良好的生物学性能,已被用于某些骨缺损修复;新短肽P17-骨形态发生蛋白2具有良好的生物相容性和成骨诱导生物活性,因此将新短肽P17-骨形态发生蛋白2与胶原基质矿化磷灰石材料制备成复合支架材料可望提升骨修复效率和效果。 目的：探讨新型P17-骨形态发生蛋白2/胶原基质矿化磷灰石复合材料的生物活性。 方法：将兔骨髓间充质干细胞分别接种于新型P17-骨形态发生蛋白2/胶原基质矿化磷灰石复合材料与胶原基质矿化磷灰石材料上,培养3,7 d后,利用RT-PCR检测细胞碱性磷酸酶 mRNA相对表达。将新型P17-骨形态发生蛋白2/胶原基质矿化磷灰石复合材料(实验组)与胶原基质矿化磷灰石材料(对照组)分别埋置于SD大鼠皮下,植入12,35 d后进行Masson染色后组织学分析。将新型P17-骨形态发生蛋白2/胶原基质矿化磷灰石复合材料(实验组)与胶原基质矿化磷灰石材料(对照组)分别植入日本大耳白兔下颌骨箱状缺损处,植入5,15周后进行大体与X射线检查。实验经中国医科大学附属口腔医院伦理委员会批准。 结果与结论：①复合材料组培养7 d的碱性磷酸酶mRNA表达高于胶原基质矿化磷灰石组(P < 0.05);②皮下埋植实验显示两组材料和组织界面均未引起明显的急性炎症反应,植入后35 d实验组可见更多的纤维细胞与材料嵌合;③骨缺损修复实验中,大体观察显示两种材料均具有良好的骨修复能力,植入5周时缺损区已有缩小趋势,植入15周缺损表面比较平整;X射线检查显示与对照组相比,实验组缺损区缩小趋势更明显;④结果表明,新型P17-骨形态发生蛋白2/胶原基质矿化磷灰石复合支架材料具有比胶原基质矿化磷灰石更为优良的生物活性与骨缺损修复能力。 ORCID: 0000-0002-1196-5954(张雪) 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     

循环轴向压缩应力增强基质依赖型组织工程骨骨再生能力的研究

目的 研究循环轴向压缩应力（CACS）对基质依赖型组织工程骨（M-TEB）骨再生能力的影响。方法 首先,在构建静态M-TEB过程中加载CACS,得到动态M-TEB;然后,对各组M-TEB进行表征,并构建动物模型来评价其骨再生能力;最后,通过转录组测序探究CACS对骨髓间充质干细胞（BMSCs）基因表达的影响,并研究M-TEB来源条件培养基对内皮祖细胞（EPCs）迁移、增殖和对BMSCs成骨分化的影响。结果 ①动态M-TEB组在骨缺损区有更多新骨生成,且骨体积分数和骨密度均显著优于假手术组和静态M-TEB组（P均＜0.01）;②前30个有显著差异（q＜0.01）的基因本体论（GO）术语主要涉及MAPK通路、细胞凋亡和血管生成等,且差异基因VEGFA在这些GO术语中出现频次最高（28次）;③相比静态M-TEB来源条件培养基,动态M-TEB来源条件培养基具有更强的促进EPCs迁移、增殖和BMSCs成骨分化的作用（P均＜0.05）, 阻断实验证实VEGFA在其中发挥重要功能。结论 CACS促进BMSCs表达和分泌VEGFA,提高动态M-TEB中VEGFA浓度,最终增强其在大鼠股骨缺损模型中的骨再生能力。     

生物源性和无机源性骨替代材料修复颅骨缺损的组织学变化

背景：目前有关生物源性和无机骨组织替代材料的研究时有报道,但是选择这两种材料对于颅骨缺损病理改变的骨增量和成骨效果的差异尚无定论。 目的：比较兔颅骨缺损再生修复中应用生物源性和无机源性骨组织替代材料引导骨组织再生的能力。 方法：建立成年新西兰兔颅顶骨3个直径8 mm洞型骨缺损模型,前方和后方洞型骨缺损区分别采用无机源性Bio-Oss骨粉与生物源性天博固齿骨粉填充并用胶原生物膜覆盖。中间洞型骨缺损区仅用胶原生物膜覆盖不做其他处理,作为对照组。 结果与结论：术后12,16,24周通过Masson三色染色图像分析显示,无机源性骨粉组和生物源性骨粉组较空白对照组新生骨量明显增加,且生物源性骨粉组新生骨量明显多于无机源性骨粉组 (P ≤ 0.05)。可见无机源性与生物源性骨粉均可起到引导新骨再生修复骨缺损的作用,但生物源性骨粉修复骨缺损效果优于无机源性骨粉。     

天然及复合海藻酸盐水凝胶改性和构建复合体系修复骨缺损北大核心

背景:作为一种骨组织工程的细胞支架材料,海藻酸盐水凝胶因其良好的生物相容性、可再生的特点受到关注,然而天然海藻酸盐水凝胶因降解缓慢、凝胶不稳定等缺陷使其在机体环境下可能无法实现预期的效果。因此,需要对天然海藻酸盐水凝胶进行改性及构建复合体系,以满足骨缺损修复所需的功能。目的:介绍天然海藻酸盐水凝胶的结构及其改性策略,复合海藻酸盐水凝胶的构建策略,强调在不同的骨缺损修复中海藻酸盐水凝胶及其复合体系所需具备的各种功能,并总结当前的研究重点和展望未来的发展趋势。方法:作者以“alginate hydrogel、bone defect、bone repair、海藻酸盐、骨缺损、骨修复”为检索词,检索1995-2021年PubMed、Web of Science、Medline、万方、中国知网和维普数据库中的相关文献,筛选后对69篇文献进行分析。结果与结论:①海藻酸盐水凝胶通过氧化及γ射线照射等处理,能够获得更快的生物降解性能,而不同的交联方式可以使其具有不同的化学结构。②通过复合体系的构建,海藻酸盐水凝胶及其复合体系能够作为细胞、生物活性因子及药物的载体,可以单独或者联合其他支架使用。③因为具备以上复杂的性能,海藻酸盐水凝胶及其复合体系在骨缺损修复中表现出良好的前景,在部分已有的研究报道中,实现了临界性骨缺损的完全骨桥接。海藻酸盐复合体系为骨修复提供了潜在的解决方案,即通过局部生物活性物质的控制性递送,实现骨缺损的加速愈合以及临界性骨缺损的愈合。④在大节段及承重骨缺损的修复中,可以联合其他高机械强度的支架,在提供机械承重的同时,增强了其他支架的骨整合能力,而这些方案能够适应不同的骨缺损修复的要求。⑤总体而言,海藻酸盐水凝胶及其复合体系在动物实验中已经显现出良好的促进骨组织修复效果,为骨组织工程修复骨缺损提供了潜在的途径,但目前尚缺少系统的临床试验,故距离其实际服务于临床工作,还需要更多的临床研究与探索。     

Dense fibrillar collagen matrices sustain osteoblast phenotype in vitro and promote bone formation in rat calvaria defect

Two pure collagen materials were prepared from acidic collagen solutions at 5 and 40?mg/mL. Benefits of collagen concentration on bone repair were evaluated in vitro with human calvaria cells and in vivo in a rat cranial defect. Both materials exhibited specific structures, 5?mg/mL was soft with an open porous network of fibrils; 40?mg/mL was stiffer with a plugged surface and bundles of collagen fibrils. Osteoblasts seeded on 5?mg/mL formed an epithelioid layer with ultrastructural characteristics of mature osteoblasts and induced mineralization. Numerous osteoblasts migrated inside 5?mg/mL, triggering reorganization of their actin cytoskeleton, whereas on 40?mg/mL osteoblasts remained in a resting state. In rat calvaria defects, both materials induced active bone formation. Dual-energy X-ray absorption bone area measures after 4 weeks averaged 84.0% with 5?mg/mL, 88.4% with 40?mg/mL, and 36.7% in the controls (p?相似文献   

两种可注射Pluronic F-127水凝胶复合物修复兔软骨缺损的效果差异

文题释义：Pluronic F-127：是一种聚氧化乙烯-聚氧化丙烯-聚氧化乙烯三嵌段共聚物,具有在低温下为液态、常温下为固态的特性,为温固化水凝胶,具有良好的生物相容性与生物可降解性。作为组织工程中的细胞支架,Pluronic F-127已被广泛应用于软骨与皮肤等的构建。 SOX9基因：在性别决定与分化过程中具有重要的作用,在胚胎发育过程中参与骨的形成,同时其也参与神经系统与胰腺的发育及肿瘤的发生。在骨骼形成过程中,SOX9通过与 DNA 特定区域结合促进间充质细胞的聚集：首先是在软骨前体细胞中,随后是在分化中的或成熟的前体细胞中表达,维持软骨细胞增殖,抑制其向肥大软骨细胞分化,因此SOX9在软骨形成过程中起着十分重要的作用。 背景：预实验显示,SOX9基因转染的骨髓间充质干细胞可在Pluronic F-127水凝胶内良好的生长与增殖,促进细胞外基质的分泌,增加软骨基质的表达。 目的：利用慢病毒基因诱导方式将SOX9基因转导至骨髓间充质干细胞中,将其与可注射Pluronic F-127水凝胶复合,观察Pluronic F-127水凝胶复合物修复软骨缺损的效果。 方法：利用慢病毒基因诱导方式将SOX9基因转导至骨髓间充质干细胞中,转染48 h后与Pluronic F-127水凝胶复合。取60只新西兰大白兔(武汉科技大学实验动物中心提供),建立右侧膝关节股骨髁软骨缺损模型,随机分3组处理：模型组缺损部位未植入任何材料,对照组植入未转染的骨髓间充质干细胞与Pluronic F-127水凝胶复合物,实验组植入SOX9基因转染的骨髓间充质干细胞与Pluronic F-127水凝胶复合物。术后4,12周取缺损部位组织,分别进行Micro-CT三维重建、苏木精-伊红染色、番红O染色、Ⅱ型胶原免疫组织化学染色与Wakitani软组织损伤修复组织学评分。实验获得武汉科技大学伦理委员会批准。 结果与结论：①术后12周Micro-CT三维重建显示,模型组缺损区域未见明显的修复,中央仍有较大的凹陷;对照组可见明显的修复,中央凹陷区域明显减小,可见较多的再生骨小梁结构;实验组缺损部位基本完成修复;②术后12周苏木精-伊红染色显示,模型组缺损区仍未见骨小梁结构,细胞分布紊乱,未见软骨陷窝;对照组可见较多的骨组织重建,缺损区域主要由软骨样组织与纤维组织填充;实验组骨组织重建较充分,缺损区域主要由软骨样细胞与软骨样细胞外基质填充,细胞呈柱状排列,与周围软骨相似;③术后12周番红O染色与Ⅱ型胶原免疫组织化学染色显示,模型组可见少量糖胺多糖表达,未见Ⅱ型胶原表达;对照组可见较多的糖胺多糖与Ⅱ型胶原表达,实验组糖胺多糖与Ⅱ型胶原表达最多;④实验组Wakitani软组织损伤修复组织学评分高于对照组与模型组(P < 0.05);⑤结果表明,负载SOX9基因转染骨髓间充质干细胞的Pluronic F-127水凝胶复合物可促进软骨缺损的修复。 ORCID: 0000-0002-9648-5297(樊薰勤) 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     

Simvastatin delivery on PEEK for bioactivity and osteogenesis enhancements

Abstract

A strategy developed for obtaining positive cellular responses remains to be focused in the filed of functional biomimetics. In this study, a hydrogel covered simvastatin-loaded polyetheretherketone (PEEK) bio-composites was constructed with the purpose of bone tissue regeneration therapy. Briefly, a three-dimensional (3D) porous structure was fabricated on PEEK surface; then the substrate was functionalized with the poly(L-lactic acid)/simvastatin porous film and hyaluronic acid hydrogel subsequently. In vitro cell attachment, proliferation, and cytoskeletal observation experiments reveal that our scaffolds show better bio-affinity due to the layer of hyaluronic acid hydrogel compared with control. Furthermore, the alkaline phosphatase activity, calcium mineral deposition evaluation, and gene expression for osteogenic potential all exhibit that the superior osteogenic differentiation of MC3T3-E1 pre-osteoblasts on our scaffolds. Therefore, our PEEK samples loaded with simvastatin and covered with hyaluronic acid hydrogel hold great potential in clinical applications for bone repair.     

Effects of crystalline phase on the biological properties of collagen–hydroxyapatite composites

The objective of this study was to investigate the effects of spatial structure and crystalline phase on the biological performance of collagen–hydroxyapatite (Col–HA) composite prepared by biomineralization crystallization. Two types of Col–HA composites were prepared using mineralization crystallization (MC composites) and pre-crystallization (PC composites), respectively. Structural characteristics were analyzed by scanning electron microscopy and transmission electron microscopy. Surface elemental compositions were measured by electron spectroscopy for chemical analysis (ESCA). These composites were used in in vivo repair of bone defects. The effects of the crystalline phase on the biological performance of Col–HA composites were investigated using radionuclide bone scan, histopathology and morphological observation. It was observed that in MC composites, HA was located on the surface of the collagen fibers and aggregated into crystal balls, whereas HA in PC composites was scattered among the collagen fibers. ESCA showed that phosphorus and calcium were 8.99% and 17.56% on MC composite surface, compared with 4.39% and 5.86% on the PC composite surface. In vivo bone defect repair experiments revealed that radionuclide uptake was significantly higher in the area implanted with the PC composite than in the contralateral area implanted with the MC composite. Throughout the whole repair process, the PC composite proved to be superior to the MC composite with regard to capillary-forming capacity and the amount of newly formed bone tissue. So it could be concluded that HA placement on collagen fibers affected the biological performance of Col–HA composites. Pre-crystallization made HA scattered among collagen fibers, creating a better structure for bone defect repair in comparison with MC Col–HA composites.     

Demineralized dentin matrix composite collagen material for bone tissue regeneration

Demineralized dentin matrix (DDM) had been successfully used in clinics as bone repair biomaterial for many years. However, particle morphology of DDM limited it further applications. In this study, DDM and collagen were prepared to DDM composite collagen material. The surface morphology of the material was studied by scanning electron microscope (SEM). MC3T3-E1 cells responses in vitro and tissue responses in vivo by implantation of DDM composite collagen material in bone defect of rabbits were also investigated. SEM analysis showed that DDM composite collagen material evenly distributed and formed a porous scaffold. Cell culture and animal models results indicated that DDM composite collagen material was biocompatible and could support cell proliferation and differentiation. Histological evaluation showed that DDM composite collagen material exhibited good biocompatibility, biodegradability and osteoconductivity with host bone in vivo. The results suggested that DDM composite collagen material might have a significant clinical advantage and potential to be applied in bone and orthopedic surgery.     

骨髓间充质干细胞复合多肽凝胶及成软骨生成因子修复兔关节软骨缺损

背景：多肽水凝胶因为其具有良好的可塑型性,能够与损伤部位很好的无缝隙结合,所以采用该材料作为支架是骨、软骨组织工程中一种可行的探索。 目的：骨髓间充质干细胞联合新型可注射多肽凝胶及成软骨生成因子修复兔关节软骨缺损,观察其修复效果。 方法：首先分离培养兔骨髓间充质干细胞,兔左侧膝关节处制备直径5 mm,深3 mm的全层骨-软骨缺损模型;右侧造模后空置作为对照。实验分为3组,单纯自组装多肽凝胶移植组,自组装多肽凝胶+成软骨因子组和自组装多肽凝胶+成软骨因子+骨髓间充质干细胞组。采用的成软骨因子包括转化生长因子β1,地塞米松和胰岛素样生长因子1,三者混合后加入到自组装多肽凝胶或骨髓间充质干细胞中。于处理后12周时处死动物行大体及组织学观察、X射线摄片、免疫组织化学法进行组织学评分评估修复情况。 结果与结论：单纯自组装多肽凝胶移植在12周后显示出非常好的修复效果,可见番红O染色,Ⅱ型胶原蛋白免疫组织化学染色强度以及组织学评分明显高于其他组(P < 0.05)。自组装多肽凝胶+成软骨因子组修复效果较好,与自组装多肽凝胶组相似,但其修复区域蛋白聚糖表达比对照组明显升高(P < 0.01)。自组装多肽凝胶+成软骨因子+骨髓间充质干细胞组修复效果不佳,12周未能完全修复缺损区域,与单纯自组装多肽凝胶组比较骨赘的形成有所增加。结果表明,单纯自组装多肽凝胶能够在原位修复骨软骨缺损并促进软骨修复,提示以自组装多肽凝胶支架移植有望提高目前修复软骨缺损的效果。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

纳米级多孔负载人骨形成蛋白2基因修饰支架对前成骨细胞株分化的影响

BACKGROUND: Bone tissue transplantation or osteogenic material filling is after used for bone defect repair. To remove autologous bone tissues can lead to additional damage and secondary deformity, therefore, it is extremely urgent to search for a new osteogenic material. OBJECTIVE: To construct the porous β-tricalcium phosphate (β-TCP)/collagen scaffold modified with human bone morphogenetic protein 2 (hBMP2) gene, and to observe its effects on differentiation of MC3T3-E1 cell lines. METHODS: The porous β-TCP/collagen scaffold modified with hBMP2 gene was prepared. Then in vitro culture system of MC3T3-E1 cell lines with composite scaffold was established. There were scaffold and plate groups, and each group was divided into two subgroups according to the different concentrations of plasmid. Samples were collected and observed morphologically by scanning electron microscope and light microscope after complex culture. After 1, 3, 7 and 14 days of induction, calcium nodules were observed through alizarin red staining, the cell cycle was detected by real-time PCR, and expressions of α I-chain collagen type I gene, Osterix and bone sialoprotein were observed. RESULTS AND CONCLUSION: The number of cells adhered, differentated and distributed on the composite scaffold was significantly higher than that of the single scaffold (P < 0.05). Alizarin red staining and real-time PCR detection showed that the osteogenesis ability of MC3T3-E1 cell lines in the scaffold group was stronger than that in the plate group. To conclude, the porous β-TCP/collagen scaffold modified with hBMP2 gene is an appropriate candidate for bone defect repair.     

Bone regeneration using an alpha 2 beta 1 integrin-specific hydrogel as a BMP-2 delivery vehicle

Non-healing bone defects present tremendous socioeconomic costs. Although successful in some clinical settings, bone morphogenetic protein (BMP) therapies require supraphysiological dose delivery for bone repair, raising treatment costs and risks of complications. We engineered a protease-degradable poly(ethylene glycol) (PEG) synthetic hydrogel functionalized with a triple helical, α2β1 integrin-specific peptide (GFOGER) as a BMP-2 delivery vehicle. GFOGER-functionalized hydrogels lacking BMP-2 directed human stem cell differentiation and produced significant enhancements in bone repair within a critical-sized bone defect compared to RGD hydrogels or empty defects. GFOGER functionalization was crucial to the BMP-2-dependent healing response. Importantly, these engineered hydrogels outperformed the current clinical carrier in repairing non-healing bone defects at low BMP-2 doses. GFOGER hydrogels provided sustained in vivo release of encapsulated BMP-2, increased osteoprogenitor localization in the defect site, enhanced bone formation and induced defect bridging and mechanically robust healing at low BMP-2 doses which stimulated almost no bone regeneration when delivered from collagen sponges. These findings demonstrate that GFOGER hydrogels promote bone regeneration in challenging defects with low delivered BMP-2 doses and represent an effective delivery vehicle for protein therapeutics with translational potential.     

Vancomycin-loaded oxidized hyaluronic acid and adipic acid dihydrazide hydrogel: Bio-compatibility,drug release,antimicrobial activity,and biofilm model

BackgroundProsthesis infection is a difficult-to-treat situation. Hydrogel is a novel biomaterial, which can be applied by simply spraying or by coating on implants before surgery and can be easily mixed with antibiotics.MethodsIn order to evaluate the potential use of antibiotic-loaded hydrogel, we incorporated vancomycin into oxidized hyaluronic acid (HA) and adipic acid dihydrazide and evaluated the drug release and antimicrobial activity against methicillin-resistant Staphylococcus aureus (ATCC 29213).ResultsThe average release percentage of vancomycin on day 3 was about 86%. The antibiotic-loaded gel was biocompatible with mesenchymal stem cell, MC3T3, and L929 cell lines. The in vitro inhibition zones of vancomycin-loaded hydrogel [500X minimal inhibition concentration (MIC), 50X MIC, 10X MIC, and blank hydrogel] were 21, 13, 9, and 5 mm, respectively. In the Ti6Al4V implant biofilm model, 0.01–1% vancomycin-loaded gel exhibited significant anti-biofilm activity, measured by the MTT assay.ConclusionsVancomycin could be loaded onto oxidized HA and adipic acid dihydrazide, which exhibited excellent drug release and in vitro antimicrobial activity with minimal cell toxicity.     

Evaluation of skeletal tissue repair,Part 2: Enhancement of skeletal tissue repair through dual-growth-factor-releasing hydrogels within an ex vivo chick femur defect model

There is an unmet need for improved, effective tissue engineering strategies to replace or repair bone damaged through disease or injury. Recent research has focused on developing biomaterial scaffolds capable of spatially and temporally releasing combinations of bioactive growth factors, rather than individual molecules, to recapitulate repair pathways present in vivo. We have developed an ex vivo embryonic chick femur critical size defect model and applied the model in the study of novel extracellular matrix (ECM) hydrogel scaffolds containing spatio-temporal combinatorial growth factor-releasing microparticles and skeletal stem cells for bone regeneration. Alginate/bovine bone ECM (bECM) hydrogels combined with poly(d,l-lactic-co-glycolic acid) (P_DLLGA)/triblock copolymer (10–30% P_DLLGA–PEG–PL_DLGA) microparticles releasing dual combinations of vascular endothelial growth factor (VEGF), chondrogenic transforming growth factor beta 3 (TGF-β3) and the bone morphogenetic protein BMP2, with human adult Stro-1 + bone marrow stromal cells (HBMSCs), were placed into 2 mm central segmental defects in embryonic day 11 chick femurs and organotypically cultured. Hydrogels loaded with VEGF combinations induced host cell migration and type I collagen deposition. Combinations of TGF-β3/BMP2, particularly with Stro-1 + HBMSCs, induced significant formation of structured bone matrix, evidenced by increased Sirius red-stained matrix together with collagen expression demonstrating birefringent alignment within hydrogels. This study demonstrates the successful use of the chick femur organotypic culture system as a high-throughput test model for scaffold/cell/growth factor therapies in regenerative medicine. Temporal release of dual growth factors, combined with enriched Stro-1 + HBMSCs, improved the formation of a highly structured bone matrix compared to single release modalities. These studies highlight the potential of a unique alginate/bECM hydrogel dual growth factor release platform for bone repair.