丝素蛋白在电纺丝法构建组织工程支架中的应用进展

丝素蛋白是天然高分子纤维蛋白,具有良好的物理和机械力学性能及生物相容性,因而在组织工程领域有着广阔的应用前景。文中对丝素蛋白的化学组成、分子结构特点、提取方法以及利用静电纺丝技术在组织工程化支架构建中的应用作了概述。总结了丝素蛋白在用于组织工程材料上的性能和优势以及在人工血管、皮肤、骨组织等工程化支架方面的应用情况,探讨了丝素蛋白支架对细胞在其上生长、增殖和功能的影响,同时对丝素蛋白在组织工程化食道支架及其他再生医学上的应用前景进行了展望。     

快速成形技术制造组织工程支架研究进展

支架作为组织工程的关键要素之一, 影响着所接种细胞的分布和增值以及新组织的形成。传统的方法虽然可以制造出各种孔隙率的支架, 但缺乏对支架多孔结构的控制。近年来, 快速成形技术发展迅速, 并成功应用于组织工程支架的制造, 实现了组织工程支架内部多孔结构与复杂外形的精确控制, 从而使得构建理想的组织工程化结构体成为可能。以下回顾了应用快速成形技术制造组织工程支架的优势与潜力, 展望了未来组织工程支架的设计制造发展方向。     

皮肤组织工程支架材料

皮肤组织工程支架材料为种子细胞提供生长和代谢的环境,是人工皮肤研究中的重要内容,可按来源分为合成支架材料和天然支架材料。近几年的研究重点是:前者通过表面仿生技术增强其对细胞的黏附性;后者通过物理或化学方法提高其力学性能和渗透性等。今后应重点研究以下内容:深入研究合成支架材料的表面改性,进一步提高其引导细胞行为的功能,促进材料对细胞的黏附;进一步提高天然支架材料的微观渗透性和生物活性,促进毛细血管的长入;制备结构仿生支架材料及高活性复合支架材料。     

肌腱组织工程支架与种子细胞研究进展

目的:综述肌腱组织工程支架材料、细胞来源、制备技术及体外构建的研究进展.方法:查阅近期肌腱组织工程研究的相关文献,对组织工程肌腱支架的材料来源、制备技术,复合细胞种类,体外构建力学刺激等进行分析、归纳.结果:肌腱组织工程支架材料有天然材料、人工合成材料及复合材料等;制备技术包括静电纺丝和编织法等;其中支架材料的表面修饰是组织工程化肌腱构建的重要环节.与肌腱材料进行复合的种子细胞有肌腱细胞、骨髓间充质干细胞及成纤维细胞等.结论:复合材料是近年肌腱组织工程支架材料研究的重点,静电纺丝技术是一种具有潜力的支架制备技术,支架材料的表面修饰可促进细胞在支架上的黏附及肌腱的形成,种子细胞的研究仍是肌腱组织工程发展的瓶颈,周期性张力的存在为组织工程化肌腱的形成创造了条件.     

电纺技术在生物医学中的应用进展

电纺技术已经成为结合多组分化合物与织造技术的关键工具,可改变电纺丝材料的化学、物理和生物特性,使其与不同的应用环境相适应。通过电纺技术制作的功能化纳米电纺丝材料,在组织工程、创伤敷料、酶的固定化和药物（基因）载体等生物医学方面得到了广泛的应用。新型的电纺技术可以进一步优化纳米电纺丝的特性,如同轴电纺、二相电纺技术;电纺丝膜的修饰也为调控电纺丝的各向异性和多孔性提供了有效的方法。该文将概述功能化电纺丝的纺织技术及修饰方法在生物医学领域的研究与应用进展。     

生物支架材料——组织工程连载之二

具有三维结构的支架材料是组织工程的核心内容之一。现有组织工程支架可分为天然生物材料、合成有机材料和无机材料三类。支架材料近年来研究十分活跃,不仅在组织工程的最早产品人工皮肤领域进行了更为完善的研究和开发,同时在诸如人工骨、软骨、神经、血管、皮肤、肝、脾、肾、膀胱等方面进行了大量研究和探索。与普通组织工程支架需要预先制备并在体外成型不同,近年来在骨和软骨组织工程实践中兴起的可注射支架具有许多优势,是未来组织工程支架发展的重要方向之一。     

组织工程面临的技术挑战与发展趋势

当前组织工程研究仍处于初级阶段,还仅仅是初步应用组织工程技术修复临床简单组织缺损,还有许多制约组织工程应用与发展的基本科学问题没有阐明.随着组织工程各个层面技术难题的逐个攻破,组织工程的内涵和外延将不断拓展,并有助于加快组织工程的产业化进程,促进临床应用.针对组织工程核心要素研究的不足,结合最新的组织工程研究进展,阐述...     

微环境对细胞的影响以及仿生学在组织工程支架中的应用

微环境影响着细胞的增殖、迁移、分化以及细胞功能,细胞微环境影响细胞命运的因素包括细胞之间相互作用、细胞与细胞外基质相互作用、可溶性信号分子以及缺氧和营养对细胞的影响。组织工程支架的制备就是要利用仿生学原理最大程度模拟细胞微环境,从而应用于细胞行为研究以及临床治疗。全面了解细胞微环境对细胞的影响因素是制备组织工程支架的重要条件,而组织工程支架的研究也进一步推动了细胞微环境对细胞影响的认识。组织工程支架研究在组织工程研究中仍具有广阔前景,新的制备工艺也在组织工程支架研究中发挥着巨大推动作用。     

半月板组织工程天然支架材料研究进展

当今社会半月板损伤十分常见。近些年,伴随生命科学和生物工程学不断发展,用组织工程原理和技术修复损伤的半月板成为热点。许多支架材料也应运而生并取得良好效果,而天然半月板支架材料起着重要的作用,如何选取理想的天然支架材料已成为这一课题的关键,其材料包含种类繁多,可分为可注射类半月板支架材料,不可注射类半月板材料。每种材料都有其独特的优势及缺陷,根据不同的需要来选择合适的材料。迄今为止,运用组织工程技术还不能完全模拟半月板组织,没有一种材料达到最理想的水平。本文着重介绍半月板组织工程天然支架材料。并对未来半月板组织工程支架材料的研究提出展望。     

溶剂浇铸/颗粒沥滤技术制备组织工程支架材料

生物可降解多孔三维细胞支架是组织工程化组织构建的基础。溶剂浇铸粒子沥滤技术是最简便、也是研究最广泛的一种多孔三维细胞支架制备技术,随着各种改进方法的出现,溶剂浇铸粒子沥滤已成为组织工程用多孔三维细胞支架的理想制备技术 。     

Perfusion seeding of channeled elastomeric scaffolds with myocytes and endothelial cells for cardiac tissue engineering

The requirements for engineering clinically sized cardiac constructs include medium perfusion (to maintain cell viability throughout the construct volume) and the protection of cardiac myocytes from hydrodynamic shear. To reconcile these conflicting requirements, we proposed the use of porous elastomeric scaffolds with an array of channels providing conduits for medium perfusion, and sized to provide efficient transport of oxygen to the cells, by a combination of convective flow and molecular diffusion over short distances between the channels. In this study, we investigate the conditions for perfusion seeding of channeled constructs with myocytes and endothelial cells without the gel carrier we previously used to lock the cells within the scaffold pores. We first established the flow parameters for perfusion seeding of porous elastomer scaffolds using the C2C12 myoblast line, and determined that a linear perfusion velocity of 1.0 mm/s resulted in seeding efficiency of 87% ± 26% within 2 hours. When applied to seeding of channeled scaffolds with neonatal rat cardiac myocytes, these conditions also resulted in high efficiency (77.2% ± 23.7%) of cell seeding. Uniform spatial cell distributions were obtained when scaffolds were stacked on top of one another in perfusion cartridges, effectively closing off the channels during perfusion seeding. Perfusion seeding of single scaffolds resulted in preferential cell attachment at the channel surfaces, and was employed for seeding scaffolds with rat aortic endothelial cells. We thus propose that these techniques can be utilized to engineer thick and compact cardiac constructs with parallel channels lined with endothelial cells. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010     

Osteochondral tissue engineering: scaffolds, stem cells and applications

Osteochondral tissue engineering has shown an increasing development to provide suitable strategies for the regeneration of damaged cartilage and underlying subchondral bone tissue. For reasons of the limitation in the capacity of articular cartilage to self-repair, it is essential to develop approaches based on suitable scaffolds made of appropriate engineered biomaterials. The combination of biodegradable polymers and bioactive ceramics in a variety of composite structures is promising in this area, whereby the fabrication methods, associated cells and signalling factors determine the success of the strategies. The objective of this review is to present and discuss approaches being proposed in osteochondral tissue engineering, which are focused on the application of various materials forming bilayered composite scaffolds, including polymers and ceramics, discussing the variety of scaffold designs and fabrication methods being developed. Additionally, cell sources and biological protein incorporation methods are discussed, addressing their interaction with scaffolds and highlighting the potential for creating a new generation of bilayered composite scaffolds that can mimic the native interfacial tissue properties, and are able to adapt to the biological environment.     

几丁聚糖在组织工程中的应用

支架材料作为组织工程的生物学植入替代物,对细胞移植与引导新组织生长有重要的作用。几丁聚糖可制成无毒性,无刺激性,生物相容性和生物可降解性良好的生物医用材料,在人工皮肤,骨修复材料,手术缝线等方面已广泛应用。本文分析了纯几丁聚糖支架结构和它与其他天然或合成材料复合的支架结构的物理、化学性质及其独特的生物学功能,同时还进一步介绍了其应用的范例并探讨了发展前景。     

Electrospinning of carboxymethyl chitin/poly(vinyl alcohol) nanofibrous scaffolds for tissue engineering applications

A novel fibrous membrane of carboxymethyl chitin (CMC)/poly(vinyl alcohol) (PVA) blend was successfully prepared by electrospinning technique. The concentration of CMC (7%) with PVA (8%) was optimized, blended in different ratios (0–100%) and electrospun to get nanofibers. Fibers were made water insoluble by chemical followed by thermal cross-linking. In vitro mineralization studies identified the ability of formation of hydroxyapatite deposits on the nanofibrous surfaces. Cytotoxicity of the nanofibrous scaffold was evaluated using human mesenchymal stem cells (hMSCs) by the MTT assays. The cell viability was not altered when these nanofibrous scaffolds were pre-washed with phosphate buffer containing saline (PBS) before seeding the cells. The SEM images also revealed that cells were able to attach and spread in the nanofibrous scaffolds. Thus our results indicate that the nanofibrous CMC/PVA scaffold supports cell adhesion/attachment and proliferation and hence this scaffold will be a promising candidate for tissue engineering applications.     

Nanofibers and their applications in tissue engineering

Developing scaffolds that mimic the architecture of tissue at the nanoscale is one of the major challenges in the field of tissue engineering. The development of nanofibers has greatly enhanced the scope for fabricating scaffolds that can potentially meet this challenge. Currently, there are three techniques available for the synthesis of nanofibers: electrospinning, self-assembly, and phase separation. Of these techniques, electrospinning is the most widely studied technique and has also demonstrated the most promising results in terms of tissue engineering applications. The availability of a wide range of natural and synthetic biomaterials has broadened the scope for development of nanofibrous scaffolds, especially using the electrospinning technique. The three dimensional synthetic biodegradable scaffolds designed using nanofibers serve as an excellent framework for cell adhesion, proliferation, and differentiation. Therefore, nanofibers, irrespective of their method of synthesis, have been used as scaffolds for musculoskeletal tissue engineering (including bone, cartilage, ligament, and skeletal muscle), skin tissue engineering, vascular tissue engineering, neural tissue engineering, and as carriers for the controlled delivery of drugs, proteins, and DNA. This review summarizes the currently available techniques for nanofiber synthesis and discusses the use of nanofibers in tissue engineering and drug delivery applications.     

静电纺丝法构建食道上皮组织

为了模拟食道上皮基膜构造,促进上皮组织的再生,以聚乳酸 (PLA) 和丝素蛋白 (SF) 为材料,利用静电纺丝法制备了PLA及PLA/SF等多孔纤维膜支架;并从猪食道粘膜组织中分离提取包括IV型胶原蛋白、层粘连蛋白、巢蛋白及蛋白聚糖等基膜蛋白的提取液,涂覆接枝于支架表面。通过扫描电镜 (SEM)、力学测试系统、体外降解等手段对支架材料的特征和性能进行检测。结果显示这两种支架的力学性能、纤维特性等均与基膜相仿;而细胞培养实验与CK14抗体进行的免疫组化分析表明,PLA/SF相对于PLA支架更能促进上皮细胞的增殖和粘附,基膜蛋白提取液的包被是有利于上皮细胞的生长和功能表达,研究结果将为工程化食道的构建提供重要的实验依据。     

Lung tissue engineering: An update

Pulmonary disease is a worldwide public health problem that reduces the life quality and increases the need for hospital admissions as well as the risk of premature death. A common problem is the significant shortage of lungs for transplantation as well as patients must also take immunosuppressive drugs for the rest of their lives to keep the immune system from attacking transplanted organs. Recently, a new strategy has been proposed in the cellular engineering of lung tissue as decellularization approaches. The main components for the lung tissue engineering are: (1) A suitable biological or synthetic three-dimensional (3D) scaffold, (2) source of stem cells or cells, (3) growth factors required to drive cell differentiation and proliferation, and (4) bioreactor, a system that supports a 3D composite biologically active. Although a number of synthetic as well biological 3D scaffold suggested for lung tissue engineering, the current favorite scaffold is decellularized extracellular matrix scaffold. There are a large number of commercial and academic made bioreactors, the favor has been, the one easy to sterilize, physiologically stimuli and support active cell growth as well as clinically translational. The challenges would be to develop a functional lung will depend on the endothelialized microvascular network and alveolar–capillary surface area to exchange gas. A critical review of the each components of lung tissue engineering is presented, following an appraisal of the literature in the last 5 years. This is a multibillion dollar industry and consider unmet clinical need.     

Premature ovarian failure and tissue engineering

Premature ovarian failure (POF) usually happens former to the age of 40 and affects the female physiological state premenopausal period. In this condition, ovaries stop working long before the expected menopausal time. Of diagnostic symptoms of the disease, one can mention amenorrhea and hypoestrogenism. The cause of POF in most cases is idiopathic; however, cancer therapy may also cause POF. Commonly utilized therapies such as hormone therapy, in-vitro activation, and regenerative medicine are the most well-known treatments for POF. Hence, these therapies may be associated with some complications. The aim of the present study is to discuss the beneficial effects of tissue engineering for fertility rehabilitation in patients with POF as a newly emerging therapy.     

Esophageal tissue engineering: an in-depth review on scaffold design

Treatment of esophageal cancer often requires surgical procedures that involve removal. The current approaches to restore esophageal continuity however, are known to have limitations which may not result in full functional recovery. In theory, using a tissue engineered esophagus developed from the patient's own cells to replace the removed esophageal segment can be the ideal method of reconstruction. One of the key elements involved in the tissue engineering process is the scaffold which acts as a template for organization of cells and tissue development. While a number of scaffolds range from traditional non-biodegradable tubing to bioactive decellularized matrix have been proposed to engineer the esophagus in the past decade, results are still not yet favorable with many challenges relating to tissue quality need to be met improvements. The success of new esophageal tissue formation will ultimately depend on the success of the scaffold being able to meet the essential requirements specific to the esophageal tissue. Here, the design of the scaffold and its fabrication approaches are reviewed. In this paper, we review the current state of development in bioengineering the esophagus with particular emphasis on scaffold design.