In vivo lamellar bone formation in fibre coated MgCHA-PCL-composite scaffolds

Bio-inspired materials with controlled topography have gained increasing interest in regenerative medicine, because of their ability to reproduce the physical features of natural extracellular matrix, thus amplifying certain biological responses both in vitro and in vivo, such as contact guidance and differentiation. However, information on the ability to adapt this high cell potential to 3D scaffolds, effective to be implanted in clinical bone defect, is still missing. Here, we examine the pattern of bone tissue generated within the implant in an ectopic model, seeding bone marrow progenitor cells onto PCL-MgCHA scaffolds. This composite material presented a porous structure with micro/nanostructured surfaces obtained by combining phase inversion/salt leaching and electrospinning techniques. Histological analysis of grafts harvested after 1-2-6 months from implantation highlights an extent of lamellar bone tissue within interconnected pores of fibre coated PCL-MgCHA composites, whereas uncoated scaffolds displayed sparse deposition of bone. Pure PCL scaffolds did not reveal any trace of bone for the overall 6 months of observation. In conclusion, we show that a structural modification in scaffold design is able to enhance bone regeneration possibly mimicking some physiological cues of the natural tissue.