Deferoxamine-loaded gelatin methacryloyl hydrogel endue 3D-printed PGCL-hydroxyapatite scaffold with angiogenesis, anti-oxidative and immunoregulatory capacities for facilitating bone healing

Promoting angiogenesis, alleviating oxidative stress injury and inflammation response are crucial for bone healing. Herein, the deferoxamine (DFO)-loaded gelatin methacryloyl (GelMA) hydrogel coating (GelMA-DFO) was constructed on the 3D-printed poly(Glycolide-Co-Caprolactone)-hydroxyapatite (PGCL-HAP) scaffold. After the hydrogel coating was established, Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM) and water contact angle measurement were employed to evaluate the characteristic and the biological properties were assessed. The modification of GelMA-DFO hydrogel endows the PGCL-HAP scaffold with angiogenic, anti-oxidative and immunoregulatory properties, overcoming the limitation of single-functionality in traditional bone tissue engineering (BTE) scaffolds. The improvement of hydrophilicity via GelMA-DFO hydrogel coating promoted cell adhesion onto the scaffold. Due to the load of DFO, the osteogenic and angiogenic effect of the scaffold in vitro were significantly enhanced. Importantly, the PGCL-HAP-DFO scaffold could effectively scavenge reactive oxygen species (ROS) and further polarized macrophage from pro-inflammation phenotype M1 to anti-inflammation phenotype M2. Experimental results in vivo further confirmed that the GelMA-DFO hydrogel coating promoted the osseointegration of PGCL-HAP scaffold via reducing inflammation, further enhancing new bone formation and tissue vascularization. Above, these results demonstrated that GelMA-DFO hydrogel endows PGCL-HAP scaffold with multiple bio-functions, thus accelerating the process of bone regeneration.