相分离法制备聚乳酸/醋酸纤维素三维微-纳米纤维多孔支架及其生物矿化活性

Fabrication and Bio-Mineralization Activity of Poly(L-lactic acid)/Cellulose Acetate There-Dimensional Micro-Nanofibrous Porous Scaffolds by Phase Separation

分别以N,N-二甲基甲酰胺、四氢呋喃、乙腈、1,4-二氧六环和N,N-二甲基乙酰胺为溶剂,在无其它添加剂条件下,通过低温淬火、萃取、洗涤和干燥得到聚乳酸(PLLA)/醋酸纤维素(CA)三维微-纳米纤维多孔支架。实验结果表明,以四氢呋喃为溶剂,得到了直径50~350 nm的三维微-纳米纤维多孔结构,该尺寸和结构刚好与天然细胞外基质(50~500 nm)相吻合。采用扫描电镜探讨了淬火时间、淬火温度、聚合物浓度和聚合物比例等条件对纤维支架形貌的影响。通过水接触角、吸水率、力学性能和体外生物活性等测试考察了CA的添加对纤维支架亲水性、力学性能和生物活性的影响。实验结果表明,与纯PLLA纤维支架相比,CA的加入改善了PLLA/CA三维微-纳米纤维多孔支架的亲水性,提高了支架的压缩强度和冲击强度,进而提高了材料的生物活性。PLLA/CA三维微-纳米纤维多孔支架的孔隙率均大于94%,比表面积均大于52 m^(2)/g,说明PLLA/CA三维微-纳米纤维多孔支架为高孔隙率和大比表面积的三维多孔材料。该孔隙率和比表面积为细胞的黏附、迁移、分化、增殖及养料的传输提供了很好的条件。

Poly(L-lactide)acid/cellulose acetate three-dimensional micro-nanofibrous porous scaffolds were prepared by low-temperature quenching,extraction,washing and drying using N,N-dimethylformamide,tetrahydrofuran,acetonitrile,1,4-dioxane and N,N-dimethylacetamide as solvent respectively,without the assistance of other additives.The experimental results show that the three-dimensional micro-nanofibrous porous structure with the diameter of 50~350 nm was obtained using tetrahydrofuran as solvent,which has the same size and structure as the natural extracellular matrix(50~500 nm).The effects of quenching time,quenching temperature,polymer concentration and PLLA/CA mass ratio etc.on the morphologies of fibrous scaffolds were investigated by SEM.The influence of the addition of CA on the hydrophilicity,mechanical properties and biological activity of fibrous scaffolds were investigated by water contact angle,water absorption,mechanical properties and in vitro biological activity tests.The experimental results show that,compared with pure PLLA fibrous scaffold,the addition of CA improves the hydrophilicity,compressive strength and impact strength of PLLA/CA three-dimensional micro-nanofibrous porous scaffolds,and then enhances the biological activity of the materials.The porosity and specific surface areas of PLLA/CA three-dimensional micro-nanofibrous porous scaffolds are all greater than 94%and 52 m^(2)/g respectively,indicating that PLLA/CA three-dimensional micro-nanofibrous porous scaffolds are three-dimensional porous materials with high porosity and large specific surface area,which will offer good conditions for cell adhesion,cell differentiation,cell prolifer and nutrients transport.