Adaptive Materials Based on Iron Oxide Nanoparticles for Bone Regeneration.

The paper provides a brief overview of the use of iron oxide nanoparticles (IONPs) in the areas of bone regenerative medicine. Reconstruction of bone defects caused by trauma, non-union, and bone tumor excision, still faces many challenges despite the intense investigations and advancement in bone-tissue engineering and bone regeneration over the past decades. IONPs have promising prospects in this field due to their controlled responsive characteristics in specific external magnetic fields and have been of great interest during the last few years. This Minireview aims to summarize the relevant progress and describes the following five aspects: (i) The general introduction of IONPs, with a focus on the magnetic properties as the base of application; (ii) using IONPs as tools to study and control stem cells for better treatment efficacy in stem-cell-based bone defect repair; (iii) the use of IONPs and their complexes in the delivery of therapeutic agents, including chemical drug molecules, growth factors, and genetic materials, to promote osteogenesis-related cell function and differentiation, healthy bone tissue growth, and functional reconstruction; (iv) magneto-mechanical actuation in the regulation of cells distribution, mechano-transduction membrane receptors activation, and mechanosensitive signaling pathways regulation, and (v) fabrication, characteristics, and in vitro and in vivo osteogenic effects of magnetic composite bone scaffolds. Ongoing prospects are also discussed.