Silk fibroin magnetoactive nanocomposite films and membranes for dynamic bone tissue engineering strategies

Bone-related diseases are one of the most common health conditions that limit the quality of life of elderly. Novel materials for bone tissue engineering that actively assist on the regeneration of bone tissue are thus needed. In this work, magnetoactive scaffolds comprised of silk fibroin (SF) with different content of filler - cobalt ferrite nanoparticles - were produced by solvent-casting and electrospinning technique and further evaluated for bone cells growth under static and dynamic magnetic stimulation. The materials were evaluated for their enhanced electric properties, analyzed through the silk fibroin beta-sheet content, an important factor for the envisaged cell stimulation strategy, which are in much higher content in films (similar to 50%) than in electrospun fibers (similar to 25%). Cell culture experiments under varying magnetic field, induced a magneto-mechanical stimulation on the materials, hence on cells, promoting improved cell viability after 4 days of culture. The scaffold morphology was found to play an important role in pre-osteoblast proliferation rate, being larger for cells growing on films, which is related to the topography of the material but also to the increased beta-sheet content. It is shown that the use of magnetic cues on magnetoactive biocompatible scaffolds is a promising strategy for remote stimulation of bone for its regeneration. Statement of Significance The use of physical stimuli such as electrical and mechanical cues have been proven a powerful tool for bone tissue engineering applications, but the use of magnetic cues on magnetoactive scaffolds has been scarcely reported. This is considered a promising strategy for remote stimulation of bone for its regeneration. The present study provides data on the evaluation of biocompatible silk fibroin scaffolds for bone cells' proper adhesion and proliferation upon the application of a magnetic stimuli using a custom-made magnetic bioreactor. The conditions created promote a biomimetic microenvironment through the application of a mechanical and electrical cues to cells. This approach is interesting since while scaffolds mimics the morphology of bone, the magnetic bioreactor provides the physical environment of bone, i.e. piezoelectricity, by generating electrical and mechanical cues with magnetic stimulation.