Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, P. R. China.
J Biomater Sci Polym Ed. 2012;23(1-4):405-24. doi: 10.1163/092050610X551970. Epub 2011 Feb 7.
Biomaterials have been playing important roles in cartilage regeneration. Although many scaffolds have been reported to enhance cartilage regeneration, none of the scaffolds available are optimal regarding mechanical properties, integration with host cartilage and providing proper micro-environment for chondrocyte attachment, proliferation and differentiation. In the current study, chitosan-modified poly(L-lactide-co-ε-caprolactone) (PLCL) scaffolds were fabricated to simulate the main biochemical components of cartilage, as well as their interaction with the aim to endow them with viscoelasticity similar to native cartilage. Porous PLCL scaffolds were fabricated with porogen-leaching, freeze-extraction and freeze-gelation before chitosan was cross-linked. The acquired porous scaffolds had pore sizes ranging from 200 to 500 μm and about 85% porosity with good interconnection between individual pores. Chitosan was successfully cross-linked to PLCL scaffolds, as validated by ninhydrin staining and X-ray photoelectron spectroscopy (XPS). The viscoelasticity of the scaffolds was similar to that of bovine cartilage and they had a relatively good recovery ratio from compression deformation, while the Young's modulus was one order of magnitude less than cartilage. Not only could the chitosan-modified PLCL scaffolds promote cell adhesion and proliferation, but also they could significantly enhance excretion of aggrecan and type-II collagen, as testified by both histology and quantitative PCR, compared with PLCL scaffolds. With the fabrication of biomimetic scaffolds, it is possible to make scaffolds for cartilage tissue engineering, which are not only biocompatible, but also have mechanical properties similar to native cartilage.
生物材料在软骨再生中发挥着重要作用。虽然已经有许多支架被报道可以增强软骨再生,但没有一种支架在机械性能、与宿主软骨的整合以及为软骨细胞附着、增殖和分化提供适当的微环境方面是理想的。在本研究中,制备了壳聚糖修饰的聚(L-丙交酯-co-ε-己内酯)(PLCL)支架,以模拟软骨的主要生化成分及其与目的的相互作用,赋予它们类似于天然软骨的粘弹性。多孔 PLCL 支架是通过致孔剂溶出、冷冻提取和冷冻凝胶化后交联壳聚糖制备的。获得的多孔支架具有 200 至 500μm 的孔径,约 85%的孔隙率,各孔之间具有良好的连通性。壳聚糖成功交联到 PLCL 支架上,这通过茚三酮染色和 X 射线光电子能谱(XPS)得到了验证。支架的粘弹性与牛软骨相似,具有相对较好的压缩变形恢复率,而杨氏模量比软骨低一个数量级。壳聚糖修饰的 PLCL 支架不仅可以促进细胞黏附和增殖,而且与 PLCL 支架相比,还可以显著增强聚集蛋白聚糖和 II 型胶原的分泌,这一点通过组织学和定量 PCR 得到了证明。通过仿生支架的制备,可以制造出具有生物相容性且机械性能类似于天然软骨的软骨组织工程支架。