ECM-inspired 3D printed polyetherimide scaffold with Arg-Gly-Asp peptides for the improvement of bioactivity and osteogenic differentiation of osteoblasts

High-performance polymers, such as polyetherimide (PEI), are promising bone biomaterials that meet the mechanical demands of bone defect repair. To achieve better therapeutic outcomes, the osteoinduction of high-performance polymers requires further improvement. In this study, the fused deposition modeling (FDM) 3D printing method was applied to fabricate orthogonal porous PEI scaffolds. Inspired by the simulation of the extracellular matrix (ECM), The polydopamine (PDA) and Arg-Gly-Asp (RGD) peptides were applied to construct an osteogenic microenvironment on PEI/PDA/RGD scaffold. The characterization, bioactivity, and osteogenic differentiation of the scaffolds were systematically investigated. The mechanical properties of the PEI/PDA/RGD scaffold were similar to those of bone tissues with favorable hydrophilicity and no biotoxicity. The adhesion, proliferation, extracellular bone matrix formation, calcium deposition, and alkaline phosphatase (ALP) vitality of MC3T3-E1 osteoblasts was higher in the PEI/PDA/RGD scaffold compared with other scaffolds. The PEI/PDA/RGD scaffold promoted the osteogenic differentiation of MC3T3-E1 osteoblasts by upregulating their gene expression of osteopontin (OPN), runt-related transcription factor 2 (RUNX-2), bone morphogenetic protein (BMP-2), osteocalcin (OCN), ALP, and especially type I collagen (COL-1). The PEI/PDA/RGD scaffold fabricated in this study is a promising bone biomaterial with appropriate mechanical properties and ideal osteogenic microenvironment, which has potential application in the field of bone defect repair. The construction of osteogenic microenvironment on 3D printed porous PEI scaffold could broaden the application of polyetherimide in bone biomaterials.