Super-paramagnetic responsive nanofibrous scaffolds under static magnetic field enhance osteogenesis for bone repair in vivo

A novel nanofibrous composite scaffold composed of super-paramagnetic gamma-Fe2O3 nanoparticles (MNP), hydroxyapatite nanoparticles (nHA) and poly lactide acid (PLA) was prepared using electrospinning technique. The scaffold well responds extern static magnetic field with typical saturation magnetization value of 0.049 emu/g as well as possesses nanofibrous architecture. The scaffolds were implanted in white rabbit model of lumbar transverse defects. Permanent magnets are fixed in the rabbit cages to provide static magnetic field for the rabbits post surgery. Results show that MNP incorporated in the nanofibers endows the scaffolds super-paramagnetic responsive under the applied static magnetic field, which accelerates new bone tissue formation and remodeling in the rabbit defect. The scaffold also exhibits good compatibility of CK, Cr, ALT and ALP within normal limits in the serum within 110 days post implantation. In conclusion, the super-paramagnetic responding scaffold with applying of external magnetic field provides a novel strategy for scaffold-guided bone repair.