A sponge scaffold with microchannels to accelerate bone repair

• A multifunctional microchannel sponge scaffold was created for bone defect repair. • Microchannel sponge scaffold improves blood clot porosity and mechanical stability. • High-porosity blood clots promote cell migration. The field of bone defect repair continues to face numerous challenges. Therefore, the development of effective bone regeneration materials remains urgently needed. This study fabricated a microchannel sponge scaffold (MS) with the assistance of 3D printing. Experimental results showed that MS increased clot porosity and mechanical stability. And MS-treated blood clots significantly enhanced cell migration compared with ordinary clots. In in vitro cell experiments, the MS loaded with blood clots and vascular endothelial growth factor (VEGF) significantly upregulated the expression levels of osteogenesis- and angiogenesis-related genes, promoting both angiogenesis as well as osteogenic differentiation. In vivo hemostasis experiments revealed that the MS significantly reduced blood loss and hemostasis time, when compared with commercially available gelatin hemostatic sponges (C-Sponge). Furthermore, in vivo experiments utilizing a rat cranial defect model indicated that the MS provided substantial support for bone defects and stimulated bone tissue formation. At 8 weeks post-transplantation, the Blood-UMS600-V group had the highest Bone Mineral Density (BMD) and Bone Volume Fraction (BV/TV) with significant differences from other groups. Histological staining revealed accelerated bone repair mechanisms involving increased collagen deposition and enhanced angiogenesis. Conclusively, MS holds clinical potential for treating bone defect bleeding and improving bone healing.