分级多孔壳聚糖/聚乳酸复合支架的制备及骨修复性能

为了仿生莲藕内部的贯穿大孔结构,以生物相容性好的壳聚糖(CS)作为基质材料,利用冰粒致孔、石蜡模具和冰模具成型3种成型方法制备了分级多孔CS支架材料,然后与力学强度较高的聚乳酸(PLLA)复合,制备网络互穿CS/PLLA复合支架。通过SEM、压缩强度测试和兔股骨髁骨缺损模型对CS/PLLA复合材料的形貌、力学强度和骨修复性能进行了表征。结果表明:利用冰模具制备的CS/PLLA复合支架能可控、批量制备,具有微米-毫米分级多孔结构,大孔孔径约为2mm,内部均匀分布着孔径约为60μm的贯穿微孔,并在微孔内形成密集的PLLA絮状网络结构。干态复合材料的压缩强度和模量分别比纯CS支架的提高了6倍和15倍。体内植入实验结果表明,CS/PLLA复合材料能够促进骨缺损的愈合,并随着新骨的形成,复合材料逐渐被降解吸收。

Fabrication and bone regenerability of chitosan/polylactic acid composite scaffolds with hierarchical porous structure

To mimic the internal large pore structure of lotus, chitosan (CS) which has good biocompatibility was used as matrix material, and three molding methods, including porogen ice, wax molding and ice molding, were used to fabricate the hierarchical porous CS scaffold materials. Then the materials were combined with polylactic acid (PLLA) which has good mechanical intensity to form CS/PLLA composite scaffolds with interpenetrating network. SEM, compressive strength test and rabbit femoral bone defect model were used to characterize the morphology, mechanical strength and bone regenerability of CS/PLLA composites. The results show that the CS/PLLA composite scaffolds fabricated by ice mould can be produced controllably in batch, and possess micron-millimeter hierarchical porous structure. The diameter of macropores is about 2 mm, micropores whose diameter is about 60 μm distribute uniformly internally, and PLLA floc network structure is formed in the micropores. Compressive strength and modulus of dry composite are improved 6 times and 15 times respectively than that of pure CS scaffolds. Implant test results show that CS/PLLA composites can promote the healing of bone defects, and the composites is gradually absorbed with the formation of new bone.