Cu/Gd co-doped hydroxyapatite/PLGA composites enhance MRI imaging and bone defect regeneration

Abstract Background The hydroxyapatite (HA)/poly(lactide-co-glycolide) acid (PLGA) composite material is one of the most widely used orthopedic implant materials with good biocompatibility and plasticity. In recent years, cation doping has increased the number of its possible biological applications. Conventional HA/PLGA composite cannot be observed using X-rays after implantation in vivo and does not lead to good osteogenic induction results. Cu can regulate the proliferation and differentiation of osteoblasts, while Gd can effectively enhance the magnetic resonance imaging ability of materials.Methods In this study, a Cu/Gd@HA/PLGA composite was prepared to explore whether the introduction of Cu and Gd into a HA/PLGA composite could enhance the osteogenic ability of osteoblasts, the in vivo bone defect repair ability, and the magnetic resonance imaging (MRI) characteristics.Results The characterization of materials confirmed that the Cu/Gd@HA has HA morphology and crystal structure. The Cu/Gd@HA/PLGA composite material has excellent nuclear magnetic imaging ability, porosity and hydrophilicity, which can promote cell adhesion and implant detection.The results of in vitro experiments confirmed that the Cu/Gd@HA/PLGA composite enhanced the proliferation, differentiation, and adhesion ability of MC3T3-E1 cells and upregulated the expression of COL-1 and BMP-2 at the gene and protein levels. In vivo, the Cu/Gd@HA/PLGA composite still showed good T1-weighted MRI abilities and effectively enhanced the bone defect healing rate in rats.Conclusion These findings indicate that the Cu/Gd@HA/PLGA composites can effectively improve the T1-weighted magnetic resonance imaging ability of the materials, promote the proliferation and differentiation of osteoblasts in vitro, and increase the rate of bone defect healing in vivo.