Mussel-Inspired Gold Nanoparticle and PLGA/L-Lysine-g-Graphene Oxide Composite Scaffolds for Bone Defect Repair

Purpose: Insufficient biological activity heavily restricts the application and development of biodegradable bone implants. Functional modification of bone implants is critical to improve osseointegration and bone regeneration. Methods: In this study, L-lysine functionalized graphene oxide (Lys-g-GO) nanoparticles and polydopamine-assisted gold nanoparticle (AuNPs-PDA) coatings were applied to improve the biological function of PLGA scaffold materials. The effects of Lys-g-GO nanoparticles and AuNPs-PDA functionalized coatings on the physicochemical properties of PLGA scaffolds were detected with scanning electron microscopy (SEM), contact angle measurement, and mechanical testing instruments. In vitro, the effects of composite scaffolds on MC3T3-E1 cell proliferation, adhesion, and osteogenic differentiation were studied. Finally, a radial defect model was used to assess the effect of composite scaffolds on bone defect healing. Results: The prepared AuNPs-PDA@PLGA/Lys-g-GO composite scaffolds exhibited excellent mechanical strength, hydrophilicity and antibacterial properties. In vitro, this composite scaffold can significantly improve osteoblast adhesion, proliferation, osteogenic differentiation, calcium deposition, and other cell behaviour. In vivo, this composite scaffold can significantly promote the new bone formation and collagen deposition in the radial defect site and presented good biocompatibility. Conclusion: The combination of bioactive nanoparticles and surface coatings shows considerable potential to enhance the osseointegration of bone implants.