Magnetic mesoporous bioactive glass scaffolds: preparation, physicochemistry and biological properties

The magnetic 10Fe5Ca MBG scaffolds (Fe₃O₄-CaO-SiO₂-P₂O₅ system) have been prepared by a combination of polyurethane sponge and P123 as co-templates and an evaporation-induced self-assembly (EISA) process through the substitution of Fe₃O₄ for CaO in the 15Ca MBG scaffolds (CaO-SiO₂-P₂O₅ system). The structure, magnetic heating, drug release, physicochemical and biological properties were systematically investigated. The results showed that the 10Fe5Ca MBG scaffolds had the interconnected macroporous structure with pore sizes ranging from 200 to 400 μm and the mesoporous wall with a peak pore size of ca. 3.34 nm. Also, the 10Fe5Ca MBG scaffolds exhibited similar mechanical strength, apatite-forming ability and sustained drug release behavior compared to the 15Ca MBG scaffolds. Importantly, the substitution of Fe₃O₄ for CaO in the MBG scaffolds induced a slower ion dissolution rate and more significant potential to stabilize the pH environment, and facilitated osteoblast cell proliferation, alkaline phosphatase (ALP) activity and osteogenic expression. In particular, the 10Fe5Ca MBG scaffolds could generate heat in an alternating magnetic field. Therefore, the magnetic 10Fe5Ca MBG scaffolds have potential for the regeneration of the critical-size bone defects caused by bone tumors by a combination of magnetic hyperthermia and local drug delivery therapy.