Magnetic scaffolds incorporated with iron oxide nanoparticles (IONPs) are biocompatible and present excellent osteogenic properties. However, the underlying mechanism is unclear. In this study, 3D-printed poly(lactic-co-glycolic acid) scaffolds were coated with IONPs using layer-by-layer assembly (Fe-scaffold) to prepare magnetic scaffolds. The effects of this modification on osteogenesis were investigated by comparison with untreated scaffolds (Uncoated-scaffold). The results showed that the proliferation of rat bone mesenchymal stem cells (rBMSCs) on the Fe-scaffold was enhanced compared with those on the Uncoated-scaffold (p < 0.05). The alkaline phosphatase activity and expression levels of osteogenic-related genes of cells on the Fe-scaffold were higher than those on the Uncoated-scaffold (p < 0.05). Fe-scaffold was found to promote the cell adhesion compared with Uncoated-scaffold, including increasing the adhered cell number, promoting cell spreading and upregulating the expression levels of adhesion-related genes integrin α1 and β1 and their downstream signaling molecules FAK and ERK1/2 (p < 0.05). Moreover, the amount of new bone formed in rat calvarial defects at 8 weeks decreased in the order: Fe-scaffold > Uncoated-scaffold > Blank-control (samples whose defects were left empty) (p < 0.05). Therefore, 3D magnetic nanocomposite scaffolds enhanced the osteogenic capacities of rBMSCs in vitro and in a rat calvarial bone defect model by promoting cell adhesion. The mechanisms were attributed to the alteration in its hydrophilicity, surface roughness, and chemical composition.
Keywords: 3D printing; bone regeneration; cell adhesion; magnetic scaffold; osteogenic differentiation.
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