Preparation And Performance Of Porous PLA/KGM Composite Cartilage Tissue Engineering Scaffold

Due to the fact that the cartilage has special structure and compositions,it’s difficult to be repaired once damaged.Therefore,the research of cartilage tissue engineering has very important significance and application value.Among the common preparation methods of cartilage tissue engineering scaffold materials,electrospinning has been widely concerned and applied because it can imitate natural extracellular matrix.However,there are still some disadvantages such as poor mechanical properties of prepared materials.In this paper,the PLA/KGM porous cartilage repair scaffolds with "sandwich"structure were prepared by electrospinning and freeze drying methods using the biodegradable macromolecule konjac glucomannan(KGM)and biocompatible polylactic acid(PLA)as raw materials.The compositions,structures and properties of the scaffolds were investigated and the results were shown as follows.(1)The optimum spinning conditions of PLA were discussed by orthogonal experiment using the polylactic acid(PLA)as raw materials.The electrospinning technology was used as the preparation method.The orthogonal experimental results showed the optimum technological conditions for the preparation of PLA fiber materials.The PLA spinning solution concentration was 6%(w/v);the voltage was 18KV and the receiving distance between positive and negative was 10cm.According to the above technological conditions,we found that the fiber diameter mainly distributed in the range of 0.6-1.0μm,and the fiber was smooth and straight.The cytotoxicity tests showed the cytotoxicity of the fibrous material was 0 or 1,with no cytotoxicity.The results of cell compatibility showed that the PLA fiber materials had good cell compatibility.(2)The KGM porous membrane was prepared by casting and freeze-drying methods using the konjac glucomannan(KGM)as raw materials.According to comprehensive mechanical properties,the porous membrance was investaged by different cross-linking processes with the cross-linking time of 4h,8h and 12h,respectively.Finally,the KGM porous membrane with the cross-linking time of 12h was selected as the basal layer of composite scaffold.And its tensile strength was 4.60MPa.The cytotoxicity tests showed the cytotoxicity of the fibrous material was 0 or 1,with no cytotoxicity.(3)The PLA/KGM porous scaffolds with "sandwich" structure were prepared by the optimum electrospinning PLA fiber on both sides of KGM(the middle layer)which was corss-linked for 12h.The results showed that the pore size of the scaffold material mainly distributed in the range of 50-200μm with a porosity of 96%;the mechanical properties of the scaffold material showed that the tensile strength was 4.87 Mpa;vitro degradation experiments showed that the degradation rate of scaffold material was 64.8%on the 90th day when immersed in PBS solution at 37℃.The KGM layer of the scaffold material was completely degraded and the remaining part was PLA layer.The material degradation cycle can basically meet the new bone repair cycle.The cytotoxicity tests showed the cytotoxicity of the fibrous material was 0 or 1,with no cytotoxicity.The prepared scaffold materials can meet basic requirements of cartilage tissue engineering on porous biomaterials well.