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Tissue Eng. Part C:开发出一种构建组织工程支架的新方法

  1. 低压发泡
  2. 前交叉韧带
  3. 支架
  4. 组织工程
  5. 骨填充材料

来源:生物谷 2012-11-18 11:27

美国西北大学研究人员开发出一种构建用于组织工程的支架材料的新方法,从而提供一种比当前技术更灵活而且更不耗时的替代性选择。 描述这项研究结果的论文,“Low-Pressure Foaming: A Novel Method for the Fabrication of Porous Scaffolds for Tissue Engineering”发表在2012年2月份那期的Tissue Engi

美国西北大学研究人员开发出一种构建用于组织工程的支架材料的新方法,从而提供一种比当前技术更灵活而且更不耗时的替代性选择。

描述这项研究结果的论文,“Low-Pressure Foaming: A Novel Method for the Fabrication of Porous Scaffolds for Tissue Engineering”发表在2012年2月份那期的Tissue Engineering Part C期刊上。

研究人员通过组织工程寻求再生因为损伤或疾病受到伤害的诸如骨骼和软骨之类的人类组织。支架---人工合成的网格状结构,能够支持组织形成--在这种过程中提供支持生长中的细胞的模板,因而是必不可少的。经过一段时间后,这种支架整合进身体同时留下在它上面再生的组织。

人们通常设计带有孔的支架材料,以便允许细胞在整个材料中迁移。美国西北大学麦考密克工程学院生物医学工程教授Guillermo Ameer也是这所大学芬伯格医学院的教授。他说,这些孔经常是通过使用盐、糖或二氧化碳气体产生的,但是这些添加物有着很多缺点:它们产生不完整的孔结构而且对盐而言,在孔产生之后还需要采取冗长的工艺去除盐。

Ameer说,这些结合陶瓷纳米颗粒和弹性聚合物构造出来的新支架材料是在真空中采用一种需要高热量的称作“低压发泡(low-pressure foaming)”的工艺形成的。结果就是在支架材料中产生一系列高度相互连接的孔,而且不依赖于盐的使用。

这种新工艺构建出的支架是高度柔韧的而且人们能够根据病人的期待康复时间进行调整从而使它按照不同的速度发生降解。Ameer说,这些支架也能够被整合进纳米大小的纤维中,从而产生一系列新的机械属性和生物属性。

Ameer说,“这种技术可能非常适合用于修复前交叉韧带(anterior cruciate ligament, ACL)撕裂和作为骨填充材料(bone void filler)”。(生物谷:towersimper编译)

Low-pressure foaming: a novel method for the fabrication of porous scaffolds for tissue engineering

Eun Ji Chung, Matthew Sugimoto, Jason L. Koh, and Guillermo A. Ameer

Scaffolds for tissue engineering applications must incorporate porosity for optimal cell seeding, tissue ingrowth, and vascularization, but common fabrication methods for achieving porosity are incompatible with a variety of polymers, limiting widespread use. In this study, porous scaffolds consisting of poly(1,8-octanediol-co-citrate) (POC) containing hydroxyapatite nanocrystals (HA) were fabricated using low-pressure foaming (LPF). LPF is a novel method of fabricating an interconnected, porous scaffold with relative ease. LPF takes advantage of air bubbles that act as pore nucleation sites during a polymer mixing step. Vacuum is applied to expand the nucleation sites into interconnected pores that are stabilized through cross-linking. POC was combined with 20%, 40%, and 60% by weight HA, and the effect of increasing HA particle content on porosity, mechanical properties, and alkaline phosphatase (ALP) activity of human mesenchymal stem cells (hMSC) was evaluated. The effect of the prepolymer viscosity on porosity and the mechanical properties of POC with 40% by weight HA (POC-40HA) were also assessed. POC-40HA scaffolds were also implanted in an osteochondral defect of a rabbit model, and the explants were assessed at 6 weeks using histology. With increasing HA content, the pore size of POC-HA scaffolds can be varied (85 to 1,003 μm) and controlled to mimic the pore size of native trabecular bone. The compression modulus increased with greater HA content under dry conditions and were retained to a greater extent than with porous scaffolds fabricated using salt-leaching under wet conditions. Furthermore, all POC-HA scaffolds prepared using LPF supported hMSC attachment, and an increase in ALP activity correlated with an increase in HA content. An increase in the prepolymer viscosity resulted in increased compression modulus, greater distance between pores, and less porosity. After 6 weeks in vivo, cell and tissue infiltration was present throughout the scaffold. This study describes a novel method of creating porous osteoconductive POC scaffolds without the need for porogen leaching and provides the groundwork for applying LPF to other elastomers and composites.

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