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

Supplementary material associated with this article can be found, in the online version, at doi:10.1016/j.mtla.2020.100709.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 ?-sheet content, an important factor for the envisaged cell stimulation strategy, which are in much higher content in films (~50%) than in electrospun fibers (~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 ?-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.This work was supported by National funds through FCT (Fundação para a Ciência e Tecnologia) and by ERDF through COMPETE2020- Programa Operacional Competitividade e Internacionalização (POCI) in the framework of the Strategic Programs UID/FIS/04650/2019, UID/BIO/04469/2019 and projects PTDC/BTM-MAT/28237/2017 and PTDC/EMD-EMD/28159/2017. The work was also supported by FCT through project Lung Check ENMed/0049/2016. R.B.P., M.M.F. and C.M.C thanks FCT for the grant SFRH/BD/140698/2018, SFRH/BPD/121464/2016, and SFRH/BPD/112547/2015, respectively. C. Ribeiro thanks the FCT for the contract under the Stimulus of Scientific Employment (DL57/2016 junior researcher contract). Finally, the authors acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3- R (AEI/FEDER, UE) and from the Basque Government Industry and Education Departments under the ELKARTEK and PIBA (PIBA-2018-06) programs, respectively. SGIker (UPV/EHU, MICINN, GV/EJ, ERDF and ESF) support is gratefully acknowledged.