Synergistic Effect of Static Magnetic Fields and 3D-Printed Iron-Oxide-Nanoparticle-Containing Calcium Silicate/Poly-ε-Caprolactone Scaffolds for Bone Tissue Engineering.

In scaffold-regulated bone regeneration, most three-dimensional (3D)-printed scaffolds do not provide physical stimulation to stem cells. In this study, a magnetic scaffold was fabricated using fused deposition modeling with calcium silicate (CS), iron oxide nanoparticles (Fe 3 O 4 ), and poly-ε-caprolactone (PCL) as the matrix for internal magnetic sources. A static magnetic field was used as an external magnetic source. It was observed that 5% Fe 3 O 4 provided a favorable combination of compressive strength (9.6 ± 0.9 MPa) and degradation rate (21.6 ± 1.9% for four weeks). Furthermore, the Fe 3 O 4 -containing scaffold increased in vitro bioactivity and Wharton's jelly mesenchymal stem cells' (WJMSCs) adhesion. Moreover, it was shown that the Fe 3 O 4 -containing scaffold enhanced WJMSCs' proliferation, alkaline phosphatase activity, and the osteogenic-related proteins of the scaffold. Under the synergistic effect of the static magnetic field, the CS scaffold containing Fe 3 O 4 can not only enhance cell activity but also stimulate the simultaneous secretion of collagen I and osteocalcin. Overall, our results demonstrated that Fe 3 O 4 -containing CS/PCL scaffolds could be fabricated three dimensionally and combined with a static magnetic field to affect cell behaviors, potentially increasing the likelihood of clinical applications for bone tissue engineering.