脂肪组织工程支架材料的研究进展

组织工程的核心是建立由种子细胞和生物材料支架构成的三维空间结构复合体,生物材料是组织工程发展的关键,随着材料科学、化学和生物学的发展,各种适合细胞生长、繁殖和分化的天然和合成的可降解材料被用来制作组织工程支架。要成功构建工程化的脂肪组织,选择适当的支架     

脂肪组织工程研究进展

成功构建组织工程化脂肪的关键在于：①种子细胞的选定和获取;②具有良好生物降解性和组织相容性的三维支架材料;③种子细胞增殖和分化的微环境。本文就这三方面的研究进展综述如下：     

组织工程中胶原支架材料的研究进展

组织工程是应用工程学、生命科学的原理和方法来制备具有生物活性的人工替代物,用以维持、恢复或提高人体组织、器官的一部分或全部功能。组织工程的研究主要集中在种子细胞的选择、支架材料的制备、组织工程骨的构建及体内植入相容性情况等方面。其中生物支架材料的选择是组织、器官重建的关键因素之一。理想的细胞种植基质材料应具备：①良好的     

丝素蛋白在脂肪组织工程中的研究进展

外伤、肿瘤切除术后、先天及后天性畸形等造成的软组织缺损,不仅影响缺损部位的功能和外观,还会影响患者的身心健康.软组织缺损的修复一直是整形外科的难点之一.随着组织工程技术的进步和成熟,构建组织工程脂肪为软组织缺损的填充提供了新思路.构建工程化脂肪组织有3大要素：种子细胞、生长因子和支架材料.     

桑蚕丝低温成形组织工程支架的研究

组织工程学是材料学、工程学和生命科学共同发展并相互融合的产物,其基本思路是在体外分离、培养细胞,将一定量的细胞接种到具有一定空间结构的支架上,通过细胞之间的相互黏附、生长繁殖、分泌细胞外基质,从而形成具有一定结构和功能的组织或器官。组织工程的主要步骤为培养增殖目标组织细胞,将高浓度的细胞种植于支架材料上,在支     

半月板组织工程支架材料的研究进展

半月板是位于股骨髁与胫骨平台之间特殊的纤维软骨组织半月板缺管组织生物修复所必须的血液供应、细胞增殖及细胞外基质全成的能力,因而半月板损伤后愈合能力较弱.     

促进脂肪组织工程再血管化的相关研究进展

目的对脂肪组织工程中再血管化的研究现状进行分析,为组织工程脂肪再血管化提供理论参考。方法广泛查阅近年有关脂肪组织工程中关于再血管化研究的相关文献,围绕促血管化的5个方面,包括脂肪细胞组织结构及血供系统的特殊性、血管化的机制、种子细胞的复合、支架材料的修饰、微环境的改善,进行相关文献复习和综述。结果脂肪组织工程技术为修复软组织缺损提供了一条新思路,但目前构建成功的组织工程脂肪体积均未超过1 mL,主要与构建物内血管化程度有关,因此构建物内血供的快速重建是脂肪组织工程由基础向临床应用的关键性环节。结论促进脂肪组织工程移植物尽快再血管化,能使支架上种子细胞及时获得营养,为制备大体积组织工程脂肪提供可能,从而满足临床修复大范围软组织缺损的需要。     

关节软骨组织工程支架的研究进展

目的对软骨组织工程支架材料的研究现状进行综述,并对其发展前景进行展望。方法广泛查阅近年来关节软骨组织工程支架的相关文献,并对多种天然生物支架材料和人工合成支架材料的相关实验及临床应用效果进行分析总结。结果软骨组织工程支架的设计对软骨组织损伤修复成功与否至关重要,理想的软骨支架可以引导并促进新生软骨组织的形成。目前所应用的支架材料均有其局限性。结论进一步深入研究软骨组织工程支架,对未来临床软骨损伤的修复具有重要意义。     

软骨组织工程支架材料研究进展

软骨损伤和缺失后 ,软骨组织的自身修复能力极其有限 ,因此缺损往往不能自行修复 ,其修复和功能重建是修复重建外科十分重要的研究课题之一。现代外科的发展已使人类修复缺损软骨成为可能 ,目前临床上的修复方法主要包括植入自体生物移植物和植入软骨代用品。植入自体生物移植物 ,如骨膜、软骨膜、韧带、软骨等 ,不仅来源非常有限 ,而且会造成供区的畸形和瘢痕 ;软骨代用品 ,如冻干的同种异体软骨、人工合成材料等。植入后易引起排斥反应和感染 ,无法取得良好的术后疗效。 80年代末以来 ,国外学者研究用组织工程的方法修复软骨缺损 ,取得了…     

髓核组织工程支架材料的研究进展

椎间盘退行性病变是一类高发病率和高致残率疾病,由于椎间盘退变中晚期,髓核组织往往已经发生了不可逆退变或损坏,常规的临床治疗手段较难恢复其结构和功能,而利用组织工程学方法重建具有生物学功能髓核组织成为研究方向之一。髓核组织工程支架是髓核组织工程的重要组成部分,构建的髓核组织工程支架应模拟髓核的生长环境,为种子细胞提供粘附增殖的空间,可促进细胞的     

Biomaterials for tissue engineering

Biomaterials play a critical role in the engineering of new functional genitourinary tissues for the replacement of lost or malfunctioning tissues. They provide a temporary scaffolding to guide new tissue growth and organization and may provide bioactive signals (e.g., cell-adhesion peptides and growth factors) required for the retention of tissue-specific gene expression. A variety of biomaterials, which can be classified into three types – naturally derived materials (e.g., collagen and alginate), acellular tissue matrices (e.g., bladder submucosa and small-intestinal submucosa), and synthetic polymers [e.g., polyglycolic acid, polylactic acid, and poly(lactic-co-glycolic acid)] – have proved to be useful in the reconstruction of a number of genitourinary tissues in animal models. Some of these materials are currently being used clinically for genitourinary applications. Ultimately, the development or selection of appropriate biomaterials may allow the engineering of multiple types of functional genitourinary tissues.     

Nanofiber-based scaffolds for tissue engineering

For successful tissue engineering, it is essential to have as many biomimetic scaffolds as possible. With increasing interest in nanotechnology, development of nanofibers (n-fibers) by using the technique of electrospinning is having a new momentum. Among important potential applications of n-fiber-based scaffolds for tissue engineering represent an important advancing front. Nanoscaffolds (n-scaffolds) mimic natural extracellular matrix (ECM) and its nanoscale fibrous structure. With electrospinning, it is possible to develop submicron fibers from biodegradable polymers and these can also be used for developing multifunctional drug-releasing and bioactive scaffolds. Developed n-scaffolds are tested for their cytocompatibility using various cell models. In addition, they were seeded with cells for engineering tissue constructs. There is a large area ahead for further applications and development of these scaffolds. For instance, multifunctional scaffolds that can be used as controlled delivery system do have a potential and have yet to be investigated for improved engineering of various tissues. So far, there are only very few in vivo studies on n-scaffolds, but in the future many are expected to emerge. With the convergence of the fields of nanotechnology, drug release, and tissue engineering, new solutions could be found for the current limitations of tissue engineering. In this paper, nanoscaffolds developed by using electrospinning, used polymers so far, cytocompatibility and applications in tissue engineering are reviewed.     

Electrospun scaffolds for bone tissue engineering

Tissue engineering aims to regenerate native tissues and will represent the alternative choice of standard surgery for different kind of tissue damages. The fundamental basis of tissue engineering is the appropriate selection of scaffolds and their morphological, mechanical, chemical, and biomimetic properties, closely related to cell lines that will be seeded therein. The aim of this review is to summarize and report the innovative scientific contributions published in the field of orthopedic tissue engineering, in particular about bone tissue engineering. We have focused our attention on the electrospinning technique, as a scaffold fabrication method. Electrospun materials are being evaluated as scaffolds for bone tissue engineering, and the results of all these studies clearly indicate that they represent suitable potential substrates for cell-based technologies.     

Shape-defining scaffolds for minimally invasive tissue engineering

BACKGROUND: Minimally invasive surgical procedures are increasingly important in medicine, but biomaterials consistent with this delivery approach that allow one to control the structure of the material after implantation are lacking. Biomaterials with shape-memorizing properties could permit minimally invasive delivery of cell transplantation constructs and enable the formation of new tissues or structures in vivo in desired shapes and sizes. METHODS: Macroporous alginate hydrogel scaffolds were prepared in a number of predefined geometries, compressed into significantly smaller, different "temporary" forms, and introduced into immunocompromised mice by means of minimally invasive surgical delivery through a small catheter. Scaffolds were rehydrated in situ with a suspension of cells (primary bovine articular chondrocytes) or cell-free medium and delivered through the same catheter. Specimens were harvested at 1 hr to evaluate the efficacy of cell delivery and the recovery of scaffold geometry, and at 8 and 24 weeks to evaluate neotissue formation. RESULTS: A high percentage (88%) of scaffolds that were introduced with a catheter and rehydrated with cells had recovered their original shape and size within 1 hr. This delivery procedure resulted in cartilage structures with the geometry of the original scaffold by 2 months and histologically mature appearing tissue at 6 months. CONCLUSIONS: Shaped hydrogels, formed by covalently cross-linking, can be structurally collapsed into smaller, temporary shapes that permit their minimally invasive delivery in vivo. The rapid recovery of scaffold properties facilitates efficient cell seeding in vivo and permits neotissue formation in desired geometries.     

组织工程关节软骨梯度仿生支架的研究进展

由于良好的机械性能和生物相容性,组织工程支架已经成为修复和再生关节软骨缺损的重要方法。随着组织工程技术的不断发展,过去十年已经开发和测试了许多支架的制备和形成方法,但是理想再生支架的制备一直存在争议。关节软骨作为人体关节内的承重组织,其基质结构和细胞组成呈带状,并且从软骨表层至软骨下骨存在着几个平滑的自然梯度,包括细胞...     

Developing biodegradable scaffolds for tissue engineering of the urethra

What’s known on the subject? and What does the study add? The use of tissue engineered buccal mucosa in substitution urethroplasty removes some of the potential drawbacks of harvesting buccal mucosa however it introduces the risk of using donor tissue (allodermis) in its creation. Biocompatible biodegradable non‐woven fabrics created by electrospinning can be used as entirely synthetic matrices for seeding with autologous cells, creating tissues for implantation. This would both remove the donor tissue disease transmission risk and reduce the potential risks of harvesting buccal mucosa. While removing the risks of donor tissue, we showed that we can indeed make a replacement tissue which has similar biomechanical properties to buccal mucosa. We also found that each processing step in the creation of such a tissue is critical, for example the initial sterilisation can have a profound effect on the tissue created.

OBJECTIVE

To develop a synthetic biodegradable alternative to using human allodermis for the production of tissue‐engineered buccal mucosa for substitution urethroplasty, looking specifically at issues of sterilization and cell‐seeding protocols and, comparing the results to native buccal mucosa.

MATERIAL AND METHODS

Three methods of sterilization, peracetic acid (PAA), γ‐irradiation and ethanol, were evaluated for their effects on a biodegradable electrospun scaffold of polylactide‐co‐glycolide (PLGA, 85 : 15), to identify a sterilization method with minimal adverse effects on the scaffolds. Two protocols for seeding oral cells on the scaffold were compared, co‐culture of fibroblasts and keratinocytes on the scaffolds for 14 days, and seeding fibroblasts for 5 days then adding keratinocytes for a further 10 days. Cell viability and proliferation on the scaffolds, scaffold contraction and mechanical properties of the scaffolds with and without cells were examined.

RESULTS

γ‐irradiation and PAA sterilized scaffolds remained sterile for >3 months when incubated in antibiotic‐free culture medium, while ethanol sterilized and unsterilized samples became infected within 2–14 days. All scaffolds showed extensive contraction (up to 50% over 14 days) irrespective of the method of sterilization or the presence of cells. All methods of sterilization, particularly ethanol, reduced the tensile strength of the scaffolds. The addition of cells tended to further reduce mechanical properties but increased elasticity. The cell‐seeding protocol of adding fibroblasts for 5 days followed by keratinocytes for 10 days was the most promising, achieving a mean (sem ) ultimate tensile stress of 1.20 (0.24) × 10⁵ N/m² compared to 3.77 (1.05) × 10⁵ N/m² for native buccal mucosa, and a Young’s modulus of 2.40 (0.25) MPa, compared to 0.73 (0.09) MPa for the native buccal mucosa.

CONCLUSION

This study adds to our understanding of how sterilization and cell seeding affect the physical properties of scaffolds. Both PAA and γ‐irradiation appear to be suitable methods for sterilizing PLGA scaffolds, although both reduce the tensile properties of the scaffolds. Cells grow well on the sterilized scaffolds, and with our current protocol produce constructs which have ≈30% of the mechanical strength and elasticity of the native buccal mucosa. We conclude that sterilized PLGA 85 : 15 is a promising material for producing tissue‐engineered buccal mucosa.     

组织工程血管支架材料最适孔径的研究

目的 筛选组织工程血管支架材料的最适孔径.方法 用生物可降解材料聚β羟基丁酯(PHB)作为支架材料,运用盐析方法制成实心和不同孔径的膜片;将培养的第3代血管平滑肌细胞种植于膜片上,于培养的第1、3、7、11、14天,采用倒置显微镜下观察、苏木素-伊红(HE)染色、甲苯胺蓝染色、扫描电镜检查及噻唑蓝(MTT)比色法检测查明材料上细胞附着和生长情况.结果 倒置显微镜下无法观察附着于材料上的细胞;HE和扫描电镜标本制备过程中细胞丢失多,其不能为材料提供准确的信息;甲苯胺蓝染色可快速观察材料上细胞附着情况;MTT比色法可定量测定材料上的细胞数.经比较发现150～200 μm孔径的PHB膜片上血管平滑肌细胞附着和生长最佳.结论 150～200 μm孔径的PHB膜片最适合血管平滑肌细胞的附着和生长.