Fabrication And Properties Of Composite Three-Dimensional Nano-Scaffolds With Collagen Type ? For Catilage Tissue Engineering

Objectives:The fabrication of scaffolds with excellent tissue engineering performance and biological properties is an important part of cartilage injury repair.Currently,tissue engineering cartilage scaffolds face challenges in bioactivity,biocompatibility,morphological structure and physicochemical properties.Chondrocyte extracellular matrix provides a stable environment for biological signal transmission and chondrocyte proliferation,migration,and phenotype.The three-dimensional nano-scaffolds were prepared by using Collagen type II,Hyaluronic acid,and Chondroitin sulfate,the main components of cartilage extracellular matrix,which would ensure the bioactivity and biocompatibility of the materials while improve the structure and the physicochemical properties of the scaffolds.Then the material was modified by introducing reactive groups through chemical reactions to change the interaction and further improve the insufficiency of the scaffolds,which laid a foundation for the application of the scaffolds in cartilage repair.Methods:Col-?of porcine articular cartilage was extracted by enzyme digestion.The collagen structure and amino acid composition were determined by SDS-PAGE,FTIR and amino acid analysis.H₂O,TFE and HFIP were mixed as a solvent.The nanoscaffolds of Col-?,HA and CS with different mass ratios were prepared by electrospining.After HA and CS were oxidated by NaIO₄,electrospinning of Col-?,OHA,and OCS with different mass ratios was performed once again.The structure,morphology,thermalproperties,mechanicalproperties,hydrophilicityand hydrophobicity of the scaffolds were analyzed by FTIR,SEM,XRD,TG-DTA,tensile test and water contact angle so as to find out the best electrospining conditions and to evaluate the morphology and physicochemical properties of the scaffolds before and after oxidation.Results:Tested by FTIR and amino acid composition analysis,the collagen extracted from porcine articular cartilage accorded with the typical characteristics of collagen.In SDS-PAGE analysis,there were only two bands,chain?1 and chain?,representing Col-?with high-purity.The solvent has excellent solubility and spinnability,while H₂O,HFIP,and TFE were used as a solvent in a volume ratio of 2:1:1 to prepare electrospinning.The results of characterization of electrospun Col-?-HA-CS scaffolds showed that they had the collagen triple helix,and hydrogen bonding was the main one of intermolecular forces,presenting reticular formation of uniform slender fibers with hydrophobicity.The scaffold has good micro-morphology and thermal stability with a mass ratio of 6⁹:1:1 and the optimal tensile properties could be obtained at the mass ratio of 7:1:1.The FTIR of Col-?-OHA-OCS scaffolds showed that aldehyde groups appeared in the oxidated molecule.The results of the characterization of electrospun Col-?-OHA-OCS scaffolds indicated that they also had the triple helix of collagen,chemical bonding formed between molecules,and the intermolecular forces weakened.While the mass ratio ranged from 5¹0:1:1,the microscopic appearance of Col-?-OHA-OCS scaffolds was better than that of Col-?-HA-CS scaffolds and the droplets and adhesion on fibers were significantly decreased.The Col-?-OHA-OCS scaffolds have good thermal stability,and better hydrophilicity.The tensile properties performed well at the mass ratio of 6:1:1 and 7:1:1,but slightly worse than that of Col-?-HA-CS scaffolds.Conclusions:The electrospun Col-?-HA-CS scaffolds have good thermal,mechanical,and morphology structure characteristics.Oxidative modification of HA and CS alters its interaction with Col-?,and the molecular chain structure changes.The morphology and hydrophilicity of the Col-?-OHA-OCS scaffolds are further optimized,while the thermal stability remains unchanged,and mechanical stabilityslightly weakens.The scaffolds of chondrocyte extracellular matrix materials have advantages in biological activity and biocompatibility and modification research contributes to the morphology and physiochemical properties of the scaffolds,which is worth further study in the application of cartilage repair.