Fabrication and characterization of cobalt ferrite magnetic hydrogel combined with static magnetic field as a potential bio-composite for bone tissue engineering

Abstract Magnetism is a physical stimulus that can induce and regulate several biological responses in cells and would be promising for application in various fields of biomedical, especially tissue engineering. Magnetic properties can be provided by the construction of magnetic scaffolding or the presence of an external magnetic field. The objectives of this study were to develop a new magnetic hydrogel composite for bone tissue engineering applications by applying the cobalt ferrite nanoparticles (CoFe2O4) as magnetic agents in the structure of polyacrylic acid hydrogel. The composite hydrogel containing 5% (w/w) of nanoparticles was selected as optimal structure after comparing the results of vibrating sample magnetometer (VSM), compressive modulus, swelling, and cytotoxicity tests for all magnetic composite groups. We then investigated the effect of selected magnetic hydrogel composite, accompanied by an external static magnetic field (SMF), on the cell cytotoxicity and proliferation, osteogenic differentiation, and mineral synthesis of human dental pulp stem cells (hDPSCs), which were seeded on the magnetic hydrogel. The results show that the synergistic effect between the magnetic scaffold and the external magnetic field on the cells, increased the alkaline phosphatase activity by about 3-fold on day 14 and the synthesis of minerals was also much higher compared to the control groups. Moreover, The results also show that the effect of magnetic scaffold along with external magnetic field on the cells osteogenic differentiation was similar to the effect of osteogenic inductive culture medium on control groups. Our findings verify that our synthesized magnetic hydrogel composite would be the potential to support osteogenic differentiation of dental pulp stem cells, and combinatory application of magnetic scaffold and external magnetic field can be a promising alternative instead of chemical stimulants for cells osteogenic differentiation.