Preparation And Characterization Of Conductive Scaffolds With Antioxidant Activity

Due to the advantages of conductive polymer based hydrogels such as high electrical conductivity,good flexibility and low cost,it has been widely used in life science research in recent years,especially in tissue engineering,and many scaffold materials with conductive polymers have been prepared and applied in myocardial tissue engineering.However,the repair and reconstruction of damaged or infarcted tissue is not beneficial for it produces many free radicals.In this paper,the carboxy-terminated aniline pentamer(AP-COOH)was synthesized and modified by glutathione via an amidation reaction to obtain aniline pentamer-glutathione complex(AP-GSH)with conductivity and antioxidation capacity.Then gelatin was introduced by chemical crosslinking and freeze-drying technology to prepare conductive and antioxidant gelatin/aniline pentamer-glutathione porous scaffolds which can enhance the electrical conduction between myocardial cells,eliminate free radicals produced by damaged or infracted area and provide a good living environment for the seeding cells.The structure of aniline pentamer and glutathione modified aniline pentamer was characterized was modified by Nuclear Magnetic Resonance(1H-NMR)and Fourier transformed infrared(FT-IR)and the scaffolds were characterized by FT-IR,scanning electron microscopy(SEM).The mechanical properties of the scaffolds,such as swelling,degradation and antioxidation capacity,were measured and mechanical properties including electrical conductivity,antioxidation capacity and other physical and chemical properties were studied in detail.The results suggested that the compressive mechanical properties and toughness increased gradually with the increase of the proportion of AP-GSH in the hydrogel.Electrical experiments confirmed that the electrical conductivity increased from 4?10-5 S·cm-1 to 10?10-5 S·cm-1 with the increase of AP-GSH content in gelatin hydrogel from 6.25% to 50% and antioxidant experiments of the scaffolds confirmed that the free radical elimination and antioxidation capacity of the scaffold grew much stronger with the increase of AP-GSH content in the scaffold.Herein,in vitro model was established with BADSCs and Gel/AP-GSH,which functioned as seeding cells and scaffolds respectively.What's more,the effects on cell adhesion,proliferation and differentiation of BADSCs under normal conditions as well as ROS microenvironment conditions were investigated thoroughly.SEM and Alarmar Blue experiments showed the survival and morphology of BADSCs inside and on the surface of the scaffold were better with the increase of AP-GSH content in the scaffold.DHE staining and fluorescence quantitative results confirmed that the free radicals produced inside cells could be removed promptly with the introduction of GSH into the scaffold.And the introduction of AP-COOH enhanced the intercellular coordination capacity and radical scavenging ability via the enhancement of the electrical signals conducting between cells.Moreover,it was concluded from the staining and fluorescence quantitative analysis of cardiac-specific cTnT protein,?-actinin protein and Cx43 protein that the three myocardial specific proteins expressed much more with the increase of AP-GSH component in the scaffold under both the normal and ROS conditions.The results confirmed the improvement of the conductivity and free radical scavenging capacity of Gel/AP-GSH functional scaffold materials on BADSCs differentiation into cardiomyocytes.The study suggested that Gel/AP-GSH scaffolds carrying BADSCs were expected to be good scaffold materials for the treatment of myocardial damage and the repair and reconstruction of infracted sites.