Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, P. R. China.
J Biomater Sci Polym Ed. 2012;23(1-4):391-404. doi: 10.1163/092050610X551961. Epub 2011 Jan 21.
The combination between chitosan (CS)-based hydrophilic extracellular matrix polysaccharide and polylactide (PLA)-based hydrophobic biodegradable aliphatic polyester is a challenge in the biomaterials field. This study investigated the formation of homogeneous chitosan/poly(L-lactide) (CS/PLLA) porous composite scaffold using a novel emulsion freeze-drying technique. An oil-in-water (O/W) emulsification system was used in the presence of surfactant Tween-80, in which CS solution was used as the water phase and PLLA solution was used as the oil phase. The composite scaffolds showed well interconnected pore structures and homogenous distribution of CS and PLLA when the PLLA volume fraction was not higher than 50%. Once the PLLA content increased to 75%, SEM micrographs demonstrated that the two components present phase separation region. FT-IR analysis revealed that there are strong hydrogen bond interactions between CS and PLLA components. The porosity of the CS/PLLA composites was in the range of 85-90% and showed a slight decrease with increasing PLLA dose. The mechanical properties of the composites lay between that of the pure CS and the PLLA scaffold. The compressive strength increased from 0.17 to 0.21 MPa, while the compressive modulus increased from 2.37 to 3.38 MPa as the PLLA contents increased from 25 to 75%. In vitro cytotoxicity was evaluated by MTT assay. The results indicated that MC3T3-E1 cell viability and proliferation in the CS/PLLA scaffold were comparable to that in the CS scaffold, and much higher than that in the PLLA scaffold. The successful hydrophilic polysaccharide and hydrophobic polyester system offers a new delivery method of growth factors and a novel scaffold design for tissue engineering.
壳聚糖（CS）基亲水细胞外基质多糖与聚乳酸（PLA）基疏水可生物降解脂肪族聚酯的结合是生物材料领域的一个挑战。本研究采用新型乳液冷冻干燥技术制备了壳聚糖/聚（L-丙交酯）（CS/PLLA）多孔复合支架。在表面活性剂吐温-80 的存在下，采用油包水（O/W）乳化体系，其中 CS 溶液为水相，PLLA 溶液为油相。当 PLLA 体积分数不高于 50%时，复合支架呈现出良好的互穿孔结构和 CS 与 PLLA 的均匀分布。一旦 PLLA 含量增加到 75%时，SEM 显微照片表明这两个成分存在相分离区域。FT-IR 分析表明 CS 和 PLLA 成分之间存在强氢键相互作用。CS/PLLA 复合材料的孔隙率在 85-90%范围内，随着 PLLA 剂量的增加略有下降。复合材料的力学性能介于纯 CS 和 PLLA 支架之间。随着 PLLA 含量从 25%增加到 75%，压缩强度从 0.17 MPa 增加到 0.21 MPa，压缩模量从 2.37 MPa 增加到 3.38 MPa。通过 MTT 测定法评估体外细胞毒性。结果表明，CS/PLLA 支架中 MC3T3-E1 细胞的活力和增殖与 CS 支架相当，远高于 PLLA 支架。成功的亲水多糖和疏水聚酯系统为生长因子的输送提供了一种新方法，为组织工程设计了一种新型支架。
