Magnetic bioactive and biodegradable hollow fe-doped hydroxyapatite coated poly(l -lactic) acid micro-nanospheres

Superparamagnetic iron-substituted hydroxyapatite nanocrystals (FeHA) were used as a particulate emulsifier for the preparation of hybrid polymeric-inorganic materials by Pickering emulsion. As result, magnetic hollow micro-nanospheres (ranging from 2 μm to 500 nm) made of a polymeric shell of poly(l-lactic) acid coated with FeHA have been prepared. Several hybrid composites containing different amounts of inorganic phase loaded to the polymeric shell were prepared. The amount of FeHA strongly affected the chemical-physical features of the spheres such as size, polymer crystallinity, surface charge, and magnetization. They displayed good biocompatibility toward bone marrow mesenchymal stem cells, and the spheres coated with higher amount of FeHA exhibited better cell proliferation than those coated with lower amount. These magnetic materials have potential uses as building blocks for the preparation of scaffolds for hard tissue regeneration as well as carriers of biomolecules for nanomedical applications.