Ⅱ型胶原-丝素蛋白-透明质酸复合支架的制备及力学性能检测

Preparation and mechanical properties of collagen type II-silk fibroin-hyaluronic acid composite scaffold

背景:Ⅱ型胶原、丝素蛋白和透明质酸3种天然生物可降解材料能够为细胞提供理想的微环境,已成为理想的软骨修复支架材料。目的:将Ⅱ型胶原、丝素蛋白和透明质酸3种材料制备成软骨组织工程支架,评价其理化性质及生物力学性能。方法:采用低温3D打印技术制备Ⅱ型胶原-丝素蛋白-透明质酸复合支架,检测其微观结构、孔隙率与吸水膨胀率。采用不同的应变率对该复合支架进行压缩实验,考察支架的率相关性能;在该复合支架表面施加恒定的应力水平或恒定的应变,保持3600 s,观察其蠕变应变变化及应力松弛行为。结果与结论:①Ⅱ型胶原-丝素蛋白-透明质酸复合支架呈三维多孔结构,孔径大小一致,相通性好,孔隙率为(85.1±1.6)%,吸水膨胀率为(1071.7±131.6)%;②在不同的应变率作用下,软骨支架的压缩应力-应变曲线不重合,说明软骨支架的压缩力学性能具有率相关性;随着应变率的增加,复合支架的杨氏模量增加;③当应力水平恒定时,复合支架的蠕变应变呈现先快速增加后缓慢增加的趋势,当应力水平增加时蠕变应变也增加;④当压缩应变恒定时,支架的应力随着松弛时间先快速降低后缓慢降低,随着压缩应变的增大,不同时刻的应力都增大;⑤力学性能实验表明,制备的Ⅱ型胶原-丝素蛋白-透明质酸软骨支架力学性能特征与宿主软骨组织相似,都是非线性黏弹性材料。

BACKGROUND:Collagen type II,silk fibroin and hyaluronic acid,which can provide an ideal microenvironment for cells,have become ideal scaffold materials for cartilage repair.OBJECTIVE:To evaluate physicochemical properties and biomechanical properties of cartilage tissue engineering scaffolds prepared from collagen type II,silk fibroin and hyaluronic acid.METHODS:Collagen type II-silk fibroin-hyaluronic acid composite scaffolds were prepared by low-temperature 3D printing technology.The microstructure,porosity and water absorption of scaffold were detected.Different strain rates were used to compress the scaffold,and the rate dependent properties of the scaffold were investigated.Constant stress level or constant strain was applied on the surface of scaffold for 3600 s,and the creep behavior and stress relaxation behavior were investigated.RESULTS AND CONCLUSION:(1)The prepared scaffolds had three-dimensional porous structure,uniform pore size and good connectivity.The porosity was(85.1±1.6)%.The water absorption expansion rate was(1071.7±131.6)%.(2)Under different strain rates,the compressive stress-strain curves of cartilage scaffolds did not coincide,which indicated that the compressive mechanical properties of cartilage scaffolds were rate dependent.With the increase of strain rate,the Young’s modulus increased.(3)When the stress level was constant,the creep strain first increased rapidly and then increased slowly.When the stress level increased,the creep strain also increased.(4)When the compression strain was constant,the stress of scaffold decreased rapidly at first and then slowly with the relaxation time.With the increase of the compression strain,the stress at different times increased.(5)The mechanical properties of the collagen type II-silk fibroin-hyaluronic acid composite scaffolds are similar to those of host cartilage,which means that the prepared scaffold is a kind of nonlinear viscoelastic material.