The in vitro and in vivo biological effects and osteogenic activity of novel biodegradable porous Mg alloy scaffolds

Inspired by the process of bone reconstruction, porous scaffolds with robust osteogenesis and biodegradability would provide an ideal bone substitute for clinical practice. In this study, a novel porous Mg-Nd-Zn-Zr (JDBM) alloy scaffold coated with brushite (i.e., DCPD), denoted as JDBM-DCPD, is fabricated using a special patent template technique, which forms the main spherical pores (400-450 mu m) and smaller pores (150-250 mu m) interconnected between the adjacent main pores, facilitating nutrient penetration and cell in-growth, exhibiting sufficient mechanical properties. In vitro results demonstrate that JDBM-DCPD scaffolds promote cell in-growth and osteogenic differentiation, which significantly enhance mineralization, osteogenesis and angiogenesis-related genes expression when cultured with bone marrow mesenchymal stem cells. After implanting in vivo, JDBM-DCPD scaffolds effectively stimulate angiogenesis, osteogenesis, and remodeling with the degradation of JDBM-DCPD, and perfectly repair large bone defect in rat and rabbit models. Results from the present study provide the solid evidence that porous biodegradable Mg-based scaffolds whose pore structure can be precisely regulated by a spacer-selection technique may be a promising tissue engineering scaffolds for large bone defect repair clinically, free from any extra growth factors and live cells, such advances will make scaffold-based bone tissue repair safer, more convenient and more cost-effective. (C) 2020 Published by Elsevier Ltd.