A Comprehensive Review on Novel Graphene-Hydroxyapatite Nanocomposites For Potential Bioimplant Applications

The advancements in medical treatment necessitated the development of advanced bio-implant materials for hard tissue replacement and bone regeneration. Hydroxyapatite (HA), an extreme bioresorbable material having physicochemical similarities with natural bone, seems to be a good bioimplant. Still, the ineffective mechanical properties, viz. fracture toughness, wear resistance, and tensile strength, restrict its practical utility in bioimplants. Recently, graphene-HA nanocomposites have been explored for potential bioimplant applications ascribed to their superior biocompatibility, bioactivity, osteoconductivity, and enhanced mechanical properties. The huge surface area with a two-dimensional sheet structure facilitates graphene's strong integration with HA, thus enhancing mechanical properties. These enhanced mechanical properties of graphene-HA nanocomposite are chiefly attributed to the pull-out, ridge growth, crack deflection, and grain bridging characteristics exhibited by graphene filler in the HA matrix. Further, graphene is neutral and biocompatible, thus improving the graphene-HA nanocomposite's biocompatibility. These qualities made this nanocomposite a rising star among bio-ceramic implant materials. This review presents the current scenario on the synthesis and mechanical and biological properties of graphene-hydroxyapatite nanocomposite, which seems to be a propitious material for implants in orthopaedic applications.