Osteogenic growth peptide-loaded 3D-printed PCL scaffolds for the promotion of osteogenesis through the ERK pathway

This study aims to improve the osteogenic differentiation in vitro and bone formation in vivo through polycaprolactone (PCL) scaffolds modified with the osteogenic growth peptide (OGP). Three-dimensional (3D)-printed PCL scaffolds were designed with computer-aided design (CAD) software and fabricated by 3D layer-by-layer fused deposition. After the scaffold surfaces were modified by surface amination, the OGP was successfully loaded onto the scaffolds using a electrostatic self-assembly method. The effects of these scaffolds on the biocompatibility and osteogenic differentiation of rat bone marrow-derived stem cells (BMSCs) were studied in vitro. The modification did not influence the adhesion or proliferation, but had a notable osteogenic effect in vitro. This may be attributed to the activation of the mitogen-activated protein kinase/extracellular regulated protein kinase (MAPK/ERK) signalling pathway. Based on the results obtained after implantation into a rat cranial defect model, the PCL/OGP scaffolds notably promoted bone formation and accelerated mineralisation. The innovative modification method introduced in this work, will improve the application of PCL scaffolds in tissue engineering.