Hybrid magnetic scaffolds of gelatin-siloxane incorporated with magnetite nanoparticles effective for bone tissue engineering

Magnetism-induced applications of nanomaterials and scaffolds are currently gaining great interest for their potential applications in tissue repair and disease treatment. Here, we prepare novel magnetic scaffolds of gelatin-siloxane (GS) hybrids for bone repair and regeneration by incorporating magnetite nanoparticles (MNs). MNs were incorporated during the sol-gel process of the organic-inorganic hybrids, and highly porous scaffolds were achieved via the free-drying method. The MNs incorporated up to 3 wt% were shown to uniformly distribute within the GS matrix. The incorporated MNs significantly improved the mechanical properties of the scaffolds, including resistance to static load and dynamic storage modulus (from 100 kPa to 450 kPa). The scaffolds presented superparamagnetic behaviors, and the saturation magnetization increased with increasing MN content. The GS-MN scaffolds showed excellent bone-bioactivity, inducing apatite minerals rapidly in a body simulating medium. Rat mesenchymal stem cells cultured on the scaffolds spread better on the MN-incorporated magnetic scaffolds, and cell proliferation significantly improved on the magnetic scaffolds with respect to MN-free scaffolds. Osteogenic differentiation, as assessed by alkaline phosphatase activity of cells, was significantly higher in the magnetic scaffolds, and, furthermore, the cellular mineralization behavior also greatly improved with the incorporation of MNs. The results suggest that the MNs incorporated at small concentrations are effective in stimulating cell growth and osteogenic differentiation in the GS hybrid porous scaffolds, and thus the magnetic hybrid scaffolds may be useful for bone tissue engineering.