Mesoporous hollow Fe3O4 nanoparticles regulate the behavior of neuro-associated cells through induction of macrophage polarization in an alternating magnetic field

Abstract

Magnetic iron oxide nanoparticles have shown great research value in the field of nerve regeneration because of their characteristics of satisfactory material properties and their ability to be stimulated by an external magnetic field to enhance the function of all aspects. Nevertheless, the impact of magnetic iron oxide nanoparticles on nerve regeneration regulated by macrophage polarization has not been well studied, and it is also not clear whether the introduction of the magnetic field has a further effect. Therefore, mesoporous hollow Fe₃O₄ nanoparticles (MHFPs) were synthesized. We selected an alternating magnetic field (AMF) because it may confer a stronger effect on MHFPs as compared to a static magnetic field, and then explored the field's ability to induce macrophage polarization. Furthermore, the effects of this regulation on other neuro-associated cells were also explored. Our results suggest that MHFPs can efficiently induce polarization of macrophages at the concentration of 40 μg mL⁻¹, upregulate the expression of related genes and cytokines, and further promote the proliferation of neural stem cells and the subsequent migration of vascular endothelial cells. These effects were significantly enhanced after the application of an AMF. This work also showed that the internalization of particles is the starting point for polarization regulation.