The Preparation And Properties Of An Electrically Conductive Graphene Oxide/Chitosan Scaffold

Heart diseases are a primary cause of death and disability in many nations,accounting for approximately 15%of all human deaths.Once the myocardial cells are damaged,it is almost impossible for them to recover naturally,and the scar tissue may be deposited on the surface of the damaged myocardial tissue,further affecting the myocardial tissue function.There has been an increase in the number of surgical procedures to correct heart problems over the last decade.At present,common treatment methods for heart diseases include drug therapy,interventional therapy,surgical treatment and so on.However,there are obvious limitations because these methods cannot solve the problem of recovery of damaged myocardial tissue and lack of donor sources.Tissue engineering strategies,because of their potential at repairing and reconstructing damaged myocardium,bring new hope for patients.In addition,myocardial tissue has special electrophysiological properties,and possesses a variety of electrically conductive structures.Therefore,the development of tissue engineering scaffolds with electrical conductivity characteristics and appropriate mechanical properties is of great significance for the simulation of the conductive micro-environment of the myocardium in vivo and the construction of an engineered myocardial tissueHere,we developed conductive scaffolds with electrical conductivity and porous structure composed of chitosan?CS?blending with graphene oxide?GO?for cardiac tissue engineering.We investigated the effect of GO concentration on the physical properties and biological properties of GO/CS conductive scaffolds.Our results showed that the porosity of GO/CS conductive scaffold gradually decreases with the increase of GO concentration.When the concentration is 600 mg/L,the porosity between control group and test group has a significant difference,and the rest groups had not significant difference.All of the groups could ensure the flow of oxygen and nutrients.Meanwhile,as the concentration of GO increases,the swelling ratio of GO/CS conductive scaffolds gradually decreases,and the swelling ratio of GO/CS conductive scaffold at 600 mg/L was significantly different with control group,and all of conductive GO/CS scaffolds showed strong water absorption and water retention.The conductivity of the GO/CS scaffold increased as the concentration of GO increased,and the conductivity of the 150 mg/L GO/CS scaffold was 1.4×10^-4 S·cm^-1 which is similar with the conductivity of the heart tissue that had been reported(1-2×10^-4 S·cm^-1).MTT results showed that the toxicity of GO/CS conductive scaffold increased with the increase of GO concentration.When the concentration was 600 mg/L,the scaffold had the highest cytotoxicity,and the cell viability was the lowest?53.3%?.So it could not be used in tissue engineeringFurthermore,we used myocardial cell?H9C2 cells?as seed cells and GO/CS as scaffold materials to evaluate the effects of conductive GO/CS scaffolds on the adhesion,myocardial specific protein and gene expression of H9C2 cultured in GO/CS scaffolds.The results showed that the conductive GO/CS scaffold not only promoted the adhesion of cardiomyocytes and the formation of extracellular matrix,but also promoted the expression of cardiomyocyte-specific proteins and genes?cTnT,CX-43?compared with the control CS scaffold.This suggests that the conductive GO/CS scaffold can promote the maturation of cardiomyocytes.