Abstract: BACKGROUND: Relevant studies have shown that adding an appropriate amount of graphene oxide can improve the mechanical properties, hydrophilicity, and cell compatibility of the fiber scaffold, and has a certain ability to promote bone formation.
OBJECTIVE: To prepare egg white/polyvinyl alcohol/graphene oxide composite fiber scaffolds with different concentrations of graphene oxide and preliminary explore the biocompatibility of composite fiber scaffold in vitro.
METHODS: Electrospinning was used to prepare egg white/polyvinyl alcohol/graphene oxide composite fiber scaffolds containing 0, 0.5, 1, and 1.5 g/L graphene oxid. The morphology of the scaffold was observed by scanning electron microscope, and the mechanical properties, contact angle and equilibrium swelling ratio of the scaffold were also tested. Human umbilical vein endothelial cells and human bone marrow mesenchymal stem cells were respectively inoculated on the surface of four groups of scaffolds. The CCK-8 assay was used to detect the proliferation of the two types of cells. Live/Dead fluorescent staining was used to observe the viability of the two types of cells. The scratch test and rhodamine phalloidin staining were used to observe the migration and morphology of human umbilical vein endothelial cells.
RESULTS AND CONCLUSION: (1) Scanning electron microscope showed that with the increase of graphene oxid content, the fiber diameter of the composite scaffold increased. (2) With the increase of graphene oxid content, the hydrophilicity of the composite scaffold first decreased and then increased, and the hydrophilicity of the composite scaffold containing 0.5 g/L graphene oxid was the lowest. (3) With the increase of graphene oxid content, the Young's modulus and tensile strength of the composite scaffold first increased and then decreased, and the Young's modulus and tensile strength of the composite scaffold containing 0.5 g/L graphene oxid were the largest. (4) CCK-8 assay showed that the proliferation rate of human bone marrow mesenchymal stem cells on the composite scaffold containing 1.5 g/L graphene oxid was faster than that of the other three groups of scaffold (P < 0.05), and the proliferation rate of human umbilical vein endothelial cells on the composite scaffold containing 1 g/L graphene oxid was faster than the other three groups of scaffolds (P < 0.05). (5) With the increase of graphene oxid content, the survival rate of human bone marrow mesenchymal stem cells on the composite scaffold increased; the survival rate of human umbilical vein endothelial cells on the composite scaffold containing 1 g/L graphene oxid was the highest. (6) Scratch experiment and rhodamine phalloidin staining proved that the composite scaffold containing 1 g/L graphene oxid was most conducive to the migration and morphological expansion of human umbilical vein endothelial cells. (7) The results show that the egg white/polyvinyl alcohol/graphene oxide fiber scaffold containing 1 g/L graphene oxid has excellent fiber structure, hydrophilicity, mechanical properties and cell compatibility.

Key words: bone, materials, tissue engineering, scaffold, graphene oxide, electrospinning, egg white, vascularization, polyvinyl alcohol