Polycaprolactone-based magnetic nanocomposite scaffolds for Osteogenic Differentiation of adipose-derived mesenchymal stem cells

Abstract

Background: Bone tissue engineering (BTE) has been introduced as an alternative to conventional treatments for bone defects that do not heal spontaneously. It has recently been shown that magnetic stimulation increases stem cell attachment, growth, and osteoblastic differentiation. Type I collagen, as the main component of bone extracellular matrix, plays an essential role in cell attachment, followed by bone differentiation and bone tissue formation. The use of these features together can improve the results of tissue engineering treatment. In this study, a multi-layered nanocomposite scaffold with magnetic properties consisting of polycaprolactone and type I collagen was used to investigate the osteoblastic differentiation of mesenchymal stem cells and bone formation. Methods: Fe3O4 NPs were synthesized by co-precipitation method and characterized using SEM, VSM, and FTIR. Then, a PCL/Col I nanocomposite scaffold entrapping Fe3O4 NPs was fabricated by electrospinning and characterized using SEM, TEM, AFM, VSM, Contact Angle, tensile stretching, and FTIR. ADSCs were cultured onto PCL/Col I and PCL/Col I/Fe3O4-scaffolds. The cell viability, cell adhesion, and osteogenic differentiation were evaluated using MTT assay, SEM, DAPI staining, ALP/ARS staining, RT-PCR, and western blotting, respectively. Results: SEM, VSM, and FTIR results indicated that Fe3O4 was synthesized in nano-sized (15–30 nm) particles with spherical-shaped morphology. Fe3O4 NP improved nanocomposite scaffold strength, wettability, porosity, biocompatibility and also facilitates the ALP activity, calcium-mineralization. Finally, magnetic nanocomposite scaffolds upregulated osteogenic-related genes or proteins’ expression in seeded ADSCs with/without osteo-differentiation media conditions. Conclusion: The magnetic nanocomposite scaffolds within the natural structure of Col I increase attachment, growth, and osteogenic differentiation of ADSCs. These findings support the use of natural ECM materials alongside magnetic particles as composite scaffolds to achieve their full therapeutic potential in BTE treatments. Keywords: Bone tissue engineering, Nanocomposite scaffolds, Magnetic nanoparticles, Type I collagen, Osteogenic differentiation