Preparation and properties of porous calcium phosphate ceramic microspheres modified with magnesium phosphate surface coating for bone defect repair

Most studies have highlighted the critical influence of bioactive metal ions and pore structure on the bone repair performance of calcium phosphate. In this study, porous calcium phosphate ceramic microspheres with different porosities (45 %, 60 %, and 75 %) and pore sizes (20, 40, and 100 mu m) were constructed by combining the extrusion-rolling and pore-forming agent methods, and they were then characterized as well as their physicochemical and biological properties. On this basis, the screened porous calcium phosphate microspheres were further coated with magnesium phosphate to improve the performance of osteogenesis and angiogenesis. The results demonstrated that pore size and porosity promoted the degradation properties. However, excessive pore size and porosity also resulted in a significant decline in the mechanical performance and biological properties of the microspheres. Successful magnesium phosphate coating of ceramic microspheres did not adversely affect their physicochemical performance and allowed stable release of magnesium ions, which further enhanced the biological properties of porous ceramic microspheres, such as cell proliferation, osteogenic differentiation, and angiogenic properties. This study presents an efficient and practical processing method to further enhance the properties and expand the applications of calcium phosphate materials.