3D printed magnetoactive nanocomposite scaffolds for bone regeneration

Simulating the natural cellular environment using magnetic stimuli could be a potential strategy to promote bone tissue regeneration. This study unveiled a novel 3D printed composite scaffold containing polycaprolactone (PCL) and cobalt ferrite/forsterite core-shell nanoparticles (CFF-NPs) to investigate physical, mechanical and biological properties of magnetoactive scaffold under static magnetic field. For this purpose, core-shell structure is synthesized through a two-step synthesis strategy in which cobalt ferrite nanoparticles are prepared via sol-gel combustion method and then are coated through sol-gel method with forsterite. The characterization regarding CFF-NPs reveals that Mg2SiO4-coated CoFe2O4 nanoparticles is successfully synthesized with a core-shell structure. Afterwards, CFF-NPs are embedded within the PCL with different percentages, ultimately 3D printed scaffolds were fabricated. The in vitro assessments demonstrated that the incorporated CFF-NPs are able to cause a decrease in contact angle which was responsible for modulating purposefully the degradation rate of PCL scaffold, resulting in providing the obligatory environment for bone growth. In addition, it was observed that scaffolds including PCL combined with CFF-NPs are susceptible to improve the mechanical performance of nanocomposite scaffolds, up to a certain concentration (50% CFF-NPs and 50% PCL) with compressive modulus of 42.5 MPa. Moreover, when being exposed to simulated body fluid (SBF) solution, hydroxyapatite deposition on the surface of scaffolds was observed. Thus, these compositions may be useful for improving the osteointegration between the implant and bone tissue after implantation. Finally, the simultaneous effect of magnetic nanoparticles and magnetic field of 125 mT evaluated on cellular behavior of scaffolds. The results showed that the cell viability of all groups under magnetic field were better than that for standard condition. Likewise, SEM images of cultured cells on scaffolds confirmed that the combined effect of these factors could be lead to promote better cell adhesion, dispersion, and bone regeneration.