Superparamagnetic core-shell electrospun scaffolds with sustained release of IONPs facilitating in vitro and in vivo bone regeneration

Bone tissue engineering (BTE) is a promising approach to recover insufficient bone in dental implantations. However, the clinical application of BTE scaffolds is limited by their low mechanical strength and lack of osteoinduction. In an attempt to circumvent these limitations and improve osteogenesis, we introduced magnetic iron oxide nanoparticles (IONPs) into a core-shell porous electrospun scaffold and evaluated their impact on the physical, mechanical, and biological properties of the scaffold. We used poly(lactic-co-glycolic acid)/polycaprolactone/beta-tricalcium phosphate (PPT) scaffolds with and without gamma-Fe2O3 encapsulation, namely PPT-Fe scaffolds and PPT scaffolds, respectively. The gamma-Fe2O3 used in the PPT-Fe scaffolds was coated with polyglucose sorbitol carboxymethylether and was biocompatible. Structurally, PPT-Fe scaffolds showed uniform iron distribution encapsulated within the resorbable PPT scaffolds, and these scaffolds supported sustainable iron release. Furthermore, compared with PPT scaffolds, PPT-Fe scaffolds showed significantly better physical and mechanical properties, including wettability, superparamagnetism, hardness, tensile strength, and elasticity modulus. In vitro tests of rat adipose-derived mesenchymal stem cells (rADSCs) seeded onto the scaffolds showed increased expression of integrin beta 1, alkaline phosphatase, and osteogenesis-related genes. In addition, enhanced in vivo bone regeneration was observed after implanting PPT-Fe scaffolds in rat calvarial bone defects. Thus, we can conclude that the incorporation of IONPs into porous scaffolds for long-term release can provide a new strategy for BTE scaffold optimization and is a promising approach that can offer enhanced osteogenic capacity in clinical applications.