一种新型丝素支架材料的体内降解试验

将制备的冷冻致孔新型丝素支架材料植入兔耳皮下进行体内降解试验,评价丝素支架材料的降解规律以及生物相容性。对植入丝素支架材料的兔耳进行肉眼外观观察、组织切片观察和扫描电子显微镜观察。肉眼外观观察发现植入丝素支架材料部位的皮肤无明显红肿,经过28周左右皮下材料植入部位的突起逐渐消失;组织切片观察发现该丝素支架材料引起的组织反应较弱;扫描电子显微镜在28周时只观察到将近消失的丝素支架材料种植腔,表明材料已基本降解。相比之下28周时丝素膜仍完好,无明显降解。研究结果表明,冷冻致孔新型丝素支架材料有望开发为一种生物相容性优良的可降解吸收性组织工程支架材料。     

多孔转基因丝素支架的制备及性能测试

以2种融合了蜘蛛丝蛋白的转基因蚕丝为材料制备转基因丝素支架,通过傅里叶变换红外光谱(FTIR)、扫描电子显微镜(SEM)及压缩测试等方法表征转基因丝素支架的结构与性能变化。结果表明,转基因丝素支架的横截面以蜂窝状多孔结构为主,易于细胞的黏附和生长;再生丝素蛋白结构发生变化,β折叠结构含量提高了16.14%;力学性能得到改善,压缩模量和抗压强度分别提高了24.49%和38.11%。体外细胞培养验证了转基因支架材料生物相容性良好,对细胞增殖没有显著影响,是一种更理想的肌骨组织修复医用备选材料。研究证实了转基因蚕丝应用于再生丝素材料的可行性,为组织工程材料开发提供了新的方向。     

丝素组织工程支架的研究进展

随着组织工程学的兴起,丝素组织工程支架也已成为丝素生物材料研究的热点,以丝素为材料的多种形态的组织工程支架已用于各种细胞组织构建的研究。主要介绍丝素组织工程支架的制备,以及丝素组织工程支架用于骨、软骨、韧带和肌腱等细胞组织构建的研究进展,并展望丝素作为组织工程支架材料的研究发展趋势,以期为丝素组织工程支架的深入研究提供参考。     

我国首创:将鸵鸟、乌贼骨用于骨移植

日前,四医大口腔医学院首创采用鸵鸟骨与乌贼骨作为组织工程骨的支架材料,目前在动物体内实验已获成功,标志着我国骨组织工程的应用基础研究已经走在世界前列。毛天球教授带领他的课题组和研究生们经过近十年的努力,先后采用海南滨珊瑚、珊瑚转化的羟基磷灰石、乌贼骨转化的羟基磷灰石和经高温煅烧的鸵鸟复合陶瓷骨做组织工程骨的支架材料,将动物的骨髓基质干细胞或成骨细胞接种到这些材料中,植入到裸鼠、兔等动物的皮下组织内,可以长出活的骨组织,将这些复合着活细胞的支架材料植入到兔、羊及犬的颅骨或颌骨缺损处,在植入后4周、8周及12周…     

Ⅰ型胶原涂层聚己内酯(PCL)半月板组织工程支架的细胞亲和性

通过3D生物打印机制备聚己内酯(PCL)组织工程半月板支架,评价其生物力学特性进而筛选出具有最优力学性能的支架,而后检测支架的理化特性并在支架表面涂覆Ⅰ型胶原蛋白改善其细胞亲和性。结果显示,打印支架孔隙率分别为(61.96±0.66)%,(48.65±0.94)%和(31.76±1.50)%,孔隙率为(61.96±0.66)%的支架具有最高压缩模量,支架吸水率与支架体外降解率在第4,8,12周分别为(8.95±0.08)%,(9.24±0.08)%,(9.52±0.02)%和(0.86±0.05)%,(1.29±0.02)%,(1.56±0.13)%,扫描电镜观察计算发现支架平均孔径为500μm左右;通过细胞初始黏附试验和扫描电镜观察发现表面涂覆Ⅰ型胶原蛋白的支架其细胞黏附数明显多于未涂覆的支架;细胞增殖试验表明细胞可很好的在支架上生长增殖且细胞在表面涂覆有Ⅰ型胶原蛋白的支架上增殖性能更好。本试验初步证明,通过3D打印技术构建的PCL组织工程半月板支架经Ⅰ型胶原表面改性后其细胞亲和性得到改善。     

丝素蛋白抗凝血材料的改性研究进展

丝素蛋白是一种具有良好生物相容性的天然高分子材料,被广泛应用于药物控释、组织工程、细胞培养支架等生物医学领域。随着丝素蛋白医用材料的内植性研究逐渐深入,丝素蛋白材料抗凝血性研究成为较为活跃的新兴领域。本文重点概述了材料的抗凝血原理,并对丝素蛋白抗凝血的改性方法做了整理。     

丝素蛋白生物材料对细胞行为的影响

生物材料的相容性一直是组织工程和再生医学领域的重要议题.组织细胞能对外界环境作出不同的响应,但只有在天然生长环境中(细胞外基质)细胞才能发挥其正常的功能.因此构建基于丝素蛋白的仿生生物材料是处理生物相容性的可行途径之一.本文介绍了细胞与细胞外基质相互作用的机理,总结了近年来丝素来源的生物材料影响细胞黏附、迁移、增殖和分化等行为的因素,包括材料的化学成分、拓扑结构(纤维尺寸、支架孔径和表面特性)以及力学特性,并在此基础上讨论了存在的问题及今后的发展方向,为设计新一代的生物材料提供参考和借鉴.     

重组人骨形态发生蛋白2复合物对犬胫骨骨折愈合中4种相关细胞因子的作用

研究重组人骨形态发生蛋白2(rhBMP-2)、碱性成纤维细胞生长因子(bFGF)、纤维蛋白凝胶(FG)与妥布霉素复合物加速骨折愈合。bFGF与rhBMP-2和妥布霉素以纤维蛋白胶为载体复合,将具有抗生素缓释系统的复合物注入犬胫骨骨折处,并做内固定,于术后第2周,采集犬胫骨骨折处样品,每隔2周采集1次,共采集4次,将每次采集的样品制成组织切片,采用免疫组织化学的方法检测4种因子,并对组织切片进行分析,用多功能真彩色细胞图象分析管理系统,分析所得数据用SPSS18.0版统计软件进行统计学分析。血管内皮细胞生长因子(VEGF)在试验组第2周表达强阳性,而对照组阳性表达较弱;前4周,试验组血小板源性生长因子(PDGF)阳性率呈上升趋势,强于对照组;前8周,试验组胰岛素样生长因子(IGF)和转化生长因子-β1(TGF-β1)阳性率均高于对照组。说明bFGF与rhBMP-2和妥布霉素以纤维蛋白胶为载体的复合物在骨折愈合具有中促进细胞增殖、黏附、趋化、分化,以及骨折末端血管生长和形成的作用。     

丝胶蛋白/羟基磷灰石复合支架材料的制备及性能研究

羟基磷灰石(HA)是骨组织中无机物的主要成分。利用丝胶蛋白(SS)良好的生物相容性、生物降解性、细胞相容性,以及含有的羧基和羟基能与Ca2+紧密结合的特点,将氢氧化钙和磷酸以湿法合成的羟基磷灰石按一定的比例加入到浓缩后的丝胶蛋白溶液中,经冷冻干燥制备成丝胶蛋白/羟基磷灰石复合支架材料,期望用于骨替代和骨缺损修复。对丝胶蛋白/羟基磷灰石复合支架材料进行扫描电镜(SEM)、X射线衍射(XRD)、红外吸收光谱(FTIR)、热力学性能以及力学性能等检测,并探讨不同原料配比对材料结构与性能的影响。结果表明,丝胶蛋白/羟基磷灰石复合支架材料的孔隙分散均匀,孔隙率33.0%～62.5%;支架材料中的HA呈弱结晶态,与人体骨组织中HA的晶体态相似,丝胶蛋白分子呈β折叠结构;随着复合支架材料中HA的比例不断增加,材料的热分解温度提高,热学性能改善,当HA的质量分数达到50%时,弹性模量增大到15.64MPa,呈现较好的结构性能。     

温度敏感型可注射水凝胶的性质及应用研究进展

温度敏感型可注射水凝胶是一种对温度敏感的新型材料,可以随着温度的变化发生物理状态的变化。由于这种特性,该水凝胶材料近年来被广泛的应用于疫苗和药物控释以及组织支架工程等领域。温度敏感型可注射水凝胶材料根据其结构的不同大致可分为5个种类,论文对这5种材料的温变机制、生物相容性、毒性、可降解性等性质进行了综述,阐述了每种材料的特点,并对各个材料在药物疫苗传递系统和组织支架工程两方面的应用研究进展分别进行了归纳和总结,为温度敏感型可注射水凝胶在人类和动物医学领域的应用提供科学依据,并对其未来发展前景进行展望。     

Rapid Prototyping Technology of Tissue Engineering Scaffold

In the modern medicine field, the transplant of organ and tissue is a big problem due to serious shortage of donor organ. Artificial organ and tissue is one of solutions. With the development of science, various tissue manufacture techniques emerged. Hereinto, due to its versatility both in materials and structure, rapid prototyping technology has become one of the important methods for tissue engineering scaffold fabrication in this field.     

钻孔法增加犬半月板脱细胞基质支架孔隙率的可行性分析

为增加半月板脱细胞基质（MAM）支架的孔隙率，提高细胞植入量，笔者对犬半月板先行钻孔，再行脱细胞处理，然后检测支架的脱细胞效果、孔隙率和力学性能变化、细胞植入量及与犬骨髓间充质干细胞（BMSCs）向软骨诱导培养后糖胺聚糖和Ⅱ型胶原蛋白的表达情况。结果显示，钻孔支架的脱细胞效果良好，未见细胞核，胶原纤维结构完整；支架的孔隙率显著增大，但压缩模量变化不显著；BMSCs在钻孔支架中的植入量显著增加，细胞增殖速度和向软骨分化能力显著提高。结果表明，钻孔法增加半月板基质支架的孔隙率，不但能保持支架的力学性能、提高细胞的植入量，而且能促进细胞的增殖、分化和组织重塑，为MAM支架在组织工程半月板构建中的广泛应用奠定了基础。     

Tissue Engineering in Wound Repair: The three “R”s—Repair,Replace, Regenerate

Horses are predisposed to traumatic wounds that can be labor intensive and expensive to manage. Skin has a considerable potential for efficient and functional repair however, while cutaneous repair is a regenerative process in the fetus, this capability declines in late gestation as inflammation and scarring alter the outcome of healing. The historical gold standard for replacement of lost skin is the autologous skin graft. However, the horse's lack of redundant donor skin limits the practicality of full‐thickness grafting to smaller wounds; moreover, graft failure is relatively common in equine patients as a result of infection, inflammation, fluid accumulation beneath the graft, and motion. Tissue engineering has emerged as an interdisciplinary field with the aim to regenerate new biological material for replacing diseased or damaged tissues or organs. In the case of skin, the ultimate goal is to rapidly create a construct that effects the complete regeneration of functional skin, including all its layers and appendages. Moreover, an operational vascular and nervous network, with scar‐free integration within the surrounding host tissue, is desirable. For this to be achieved, not only is an appropriate source of cells required, but also a scaffold designed from natural or synthetic polymers. The newly created tissue might finally meet the numerous needs and expectations of practitioners and surgeons managing a catastrophic wound in a horse     

Use of tissue plasminogen activator for intraocular fibrinolysis in dogs.

Fibrin clots were induced in eyes of dogs by injection of autogenous citrated plasma into the anterior chamber. Twenty-four hours after clot formation, 0.01 ml of tissue plasminogen activator at a concentration of 1 microgram/100 microliters (group 1, n = 5) or 25 micrograms/100 microliters (group 2, n = 5) was injected into 1 anterior chamber of each dog. The contralateral eye served as a nontreated control. Serial photographs were taken of the fibrin clots after intracameral injection of tissue plasminogen activator. Computerized morphometric analysis was then used to evaluate changes in cross-sectional surface area of the fibrin clot. Significant (P less than 0.001) fibrin-clot lysis was detected in treated eyes of group-2 dogs, but was not found in treated eyes of group-1 dogs. A mean decrease of greater than 90% in clot surface area was detected by 120 minutes after injection in treated eyes of group-2 dogs.     

Adult Multipotent Stromal Cell Technology for Bone Regeneration: A Review

Since the discovery of bone marrow derived stromal cell osteogenesis in the 1960s, tissue engineering with adult multipotent stromal cells (MSCs) has evolved as a promising approach to restore structure and function of bone compromised by injury or disease. To date, accelerated bone formation with MSCs has been demonstrated with a variety of tissue engineering strategies. Though MSC bone tissue engineering has advanced over the last few decades, limitations to clinical translation remain. A current review of this promising field is presented with a specific focus on equine investigations.     

不同结构丝素蛋白对羟基磷灰石结晶的调控作用

探讨不同结构丝素蛋白对羟基磷灰石结晶的影响,可为羟基磷灰石/丝素蛋白复合材料应用于骨组织工程支架材料的研究提供依据。用中性盐水解的方法获得以无规卷曲结构为主的丝素蛋白(SF),再经乙醇处理得到具有β-折叠结构的丝素蛋白(ALSF)。以两种不同结构的丝素蛋白作为羟基磷灰石(HA)沉积的有机模板,通过共沉淀的方法获得HA/SF和HA/ALSF复合粉末。利用红外吸收光谱(FTIR)、X-射线衍射(XRD)、透射电子显微镜(TEM)等对复合材料样品进行检测和分析表明,2种丝素蛋白均对HA晶体的形核和生长产生影响,但不同结构丝素蛋白调控生成的复合材料其形貌和结晶尺寸有所不同。     

Minimally invasive synovium harvest for potential use in meniscal tissue engineering

Tissue engineering is being investigated as a means for treating avascular meniscal injury or total meniscal loss in human and veterinary patients. The purpose of this study was to determine if an arthroscopic tissue shaver can be used to collect viable synoviocytes for in vitro culture during therapeutic stifle arthroscopy, with the long term goal of producing autologous meniscal fibrocartilage for meniscal tissue engineering. Synovium was harvested arthroscopically from 13 dogs with naturally occurring cranial cruciate ligament deficiency and obtained from 5 dogs with patellar luxation via arthrotomy. Cells harvested via arthroscopy and arthrotomy were treated with a chondrogenic growth factor protocol and analyzed for meniscal-like matrix constituents including collagens type I, II, and glycosaminoglycans. Arthrotomy and Arthroscopic origin cells formed contracted tissues containing collagen I, II and small amounts of GAG. These surgical methods provide clinically relevant access to synoviocytes for potential use in meniscal tissue engineering.     

Effects of whole blood clots, time, and implant size on vascularization and collagen deposition along Teflon-ensheathed carbon fibers implanted in ewes

Seventy-two subcutaneous implants were examined to evaluate connective tissue response to Teflon-ensheathed carbon fibers and whole blood clots. Carbon fibers significantly (P less than or equal to 0.001) increased vascularization and collagen formation within the Teflon sheath. Carbon fibers provide a potentially strong scaffold that would physically support cell migration during wound healing. However, obvious foreign body reactions occurred, which indicate that further studies on the biologic features of carbon fiber are needed before carbon fibers become entirely acceptable for long-term implantation. Compared with no-clot controls, Teflon tubes containing only whole blood clots stimulated a significant (P less than or equal to 0.001) wound-healing response, including organized collagen fiber formation. Other variables tested in this study such as length and diameter of the Teflon tubes did not significantly influence connective tissue responses.