Ti@Ha-Go@Il-4 Nanocoating Modulates Macrophages And Osteogenesis

This study developed a hydroxyapatite/graphene oxide composite coating with sustained interleukin-4 (IL-4) release (Ti@HA-GO@IL-4) to precisely modulate peri-implant macrophage polarization, thereby optimizing the osteoimmunomodulatory microenvironment and osteogenic performance of implant materials. The Ti@HA-GO@IL-4 coating was fabricated on titanium implants via a synergistic electrochemical deposition and dip-coating approach. Comprehensive material characterization encompassed SEM, EDS, XRD, XPS, FTIR, Raman spectroscopy, AFM, water contact angle measurement, protein adsorption capacity, coating stability, and IL-4 release testing (ELISA and FITC fluorescence assays). RAW264.7 macrophages were co-cultured with the coating, followed by CCK-8 assay and SEM observation for cell adhesion and proliferation, immunofluorescence and flow cytometry analysis of M1/M2 polarization, ELISA detection of inflammatory (TNF-α, iNOS) and anti-inflammatory (IL-10, TGF-β) cytokines, and RT-qPCR analysis of inflammation-related genes. Macrophage-conditioned medium was used to evaluate BMSC osteogenic differentiation through alkaline phosphatase staining, alizarin red staining (for mineralization nodules), Western blotting and PCR analysis of osteogenic markers. (1) The Ti@HA-GO@IL-4 coating demonstrated optimized surface characteristics, hydrophilicity and biocompatibility; (2) It remarkably enhanced M2 macrophage polarization (p<0.01) and substantially suppressed pro-inflammatory cytokine production; (3) The conditioned medium significantly enhanced BMSC osteogenic differentiation and mineralization nodule formation. The Ti@HA-GO@IL-4 coating orchestrates macrophage polarization through sustained IL-4 release, establishing an immunomodulatory microenvironment that promotes BMSC osteogenic differentiation, offering a novel surface engineering approach for developing immunomodulatory implants.