Impact of the magnetic field on 3T3-E1 preosteoblasts inside SMART silk fibroin-based scaffolds decorated with magnetic nanoparticles

This paper reports the impact of the magnetic field on 3T3-E1 preosteoblasts within silk-fibroin scaffolds decorated with magnetic nanoparticles. Scaffolds were prepared from silk fibroin and poly(2-hydroxyethyl methacrylate) template in which magnetite nanoparticles were embedded. The presence of the magnetite specific peaks within scaffolds compositions was evidenced by RAMAN analysis. Structural investigation was done by XRD analysis and morphological information including internal structure was obtained through SEM analysis. Geometrical evaluation (size and shape), crystalline structure of magnetic nanoparticles and the morphology of the silk fibroin scaffolds were investigated by HR-TEM. Magnetic nanoparticles were distributed within scaffolds structure. Biomineralization of hydroxyapatite on silk fibroin scaffolds with and without magnetic nanoparticles was investigated by an alternate soaking process. SEM images showed that the magnetic scaffolds were covered in an almost continuously film, which has a phase with nanostructured characteristics. This phase, which has as main components Ca and P, is made of lamellar formations. The design of an original magnetic 3D cell culture setup allowed us to observe cellular modifications under the exposure to magnetic field in the presence of magnetic silk fibroin biomaterials. The cellular proliferation potential of 3T3-E1 cell line was found increased under the magnetic field, especially in the presence of the magnetite nanoparticles. In addition, we showed that the low static magnetic field positively impacts on the osteogenic differentiation potential of the cells inside the biomimetic magnetic scaffolds.