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.