Effect of nano-hydroxyapatite-coated magnetic nanoparticles on axonal guidance growth of rat dorsal root ganglion neurons

Proper extracellular substrate can stimulate neural regeneration in nerve tissue engineering, including magnetic nanoparticles (iron oxide nanoparticles, Fe₃O₄), but they are always neurotoxic, with low saturation magnetization and so on. These nanomaterials cannot be used to stimulate the growth and elongation of axons. Therefore, this work attempts to overcome these deficiencies. Nano-hydroxyapatite (n-HA) coated magnetic nanoparticles were using an ultrasound-assisted co-precipitation method. X-ray diffraction and transmission electron microscopy were used to characterize the structure and chemical composition of the produced samples. These synthesized nanomaterials were added into the primary cultured dorsal root ganglion (DRG) neurons; our results showed that n-HA-coated magnetic nanoparticles (Fe₃O₄+n-HA) can effectively increase cell viability and promote axonal elongation, which enhanced saturation magnetization. In addition, we demonstrated that axonal guidance cues Netrin-1 increase significantly after n-HA-coated magnetic nanoparticles treatment by Western blots assay. n-HA-coated magnetic particles maybe applied to enhance or accelerate nerve regeneration, and it may provide guidance for regenerating axons in future.