Graphene–Alumina Nanocomposites with Improved Mechanical Properties for Biomedical Applications

This paper presents a study on graphene platelet (GPL)-reinforced alumina (Al₂O₃) ceramic composites and the relationships between the loading of GPL and both mechanical properties and in vitro biocompatibility. Al₂O₃ powders with different GPL contents were prepared and sintered using a gas protected pressure-less furnace. The examination of the results shows the density of the composites varying from 99.2% to 95.6% with the loading of GPL from 0.75 to 1.48 vol %. Raman studies show that moderate agglomerations of GPLs occur during the ball milling process and graphitic defects were produced during the high temperature processing. Mechanical properties of the Al₂O₃ matrix are significantly improved by adding GPLs. A maximum increase of approximately 60% in flexural strength and 70% in fracture toughness are achieved by introducing 0.75 vol % GPLs. In the biocompatibility tests, it was found that cells directly seeding on top of GPL/Al₂O₃ samples showed better initial attachment (3 h after seeding) and viability (3 days after incubation) than the monolithic Al₂O₃, indicating that the GPL/Al₂O₃ composites have comparable or more favorable biocompatibility. The excellent mechanical and biomedical properties of the GPL/Al₂O₃ composites may enable them to be applied to a wide range of engineering and biomedical applications