Improved Cell Adhesion and Osteogenesis of Op-HA/PLGA Composite by Poly(dopamine)-Assisted Immobilization of Collagen Mimetic Peptide and Osteogenic Growth Peptide

A nanocomposite of poly(lactide-co-glycolide) (PLGA) and hydroxyapatite (HA) with a different grafting ratio of l-lactic acid oligomer (op-HA) showed better interface compatibility, mineralization, and osteogenetic abilities. However, surface modification of the composite is crucial to improve the osteointegration for bone regeneration. In this study, a biomimetic process via poly(dopamine) coating was utilized to prepare functional substrate surfaces with immobilized bioactive peptides that efficiently regulate the osteogenic differentiation of preosteoblasts (MC3T3-E1). Our study demonstrated that incorporation of collagen mimetic peptide significantly enhanced cell adhesion and proliferation. The immobilization of osteogenic growth peptide induced the osteodifferentiation of cells, as indicated by the alkaline phosphate activity test, quantitative real-time polymerase chain reaction analysis, and immunofluorescence staining. The mineralization on the peptide-modified substrates was also enhanced greatly. Findings from this study revealed that this biofunctionalized layer on op-HA/PLGA substrate improved mineralization and osteogenic differentiation. In conclusion, the surface modification strategy with bioactive peptides shows potential to enhance the osteointegration of bone implants.