Strontium eluting nanofibers augment stem cell osteogenesis for bone tissue regeneration

Strontium is known to offer a therapeutic benefit to osteoporotic patients by promoting bone formation. Thus, toward engineering scaffolds for bone tissue regeneration we have prepared polymer nanocomposite scaffolds by electrospinning. Strontium carbonate nanoparticles (nSrCO(3)) were added to poly(epsilon-caprolactone) (PCL) at 10 and 20 wt% to develop nanocomposite fibrous scaffolds (PCL/SrC10 and PCL/SrC20) with fiber diameter in the range of 300-500 nm. Incorporation of nSrCO(3) decreased crystallinity and the elastic modulus of PCL. The composite scaffolds released Sr2+ ions with up to 65 ppm in 4 days from the PCL/SrC20 scaffolds. Cell studies confirmed that the composite scaffold with 20% nSrCO(3) enhanced proliferation of human mesenchymal stem cells in vitro. There was marked increase in mineral deposition up to four folds in PCL/SrC20 suggesting enhanced osteogenesis. This was corroborated by increased mRNA and protein expression of various osteogenic markers such as BMP-2, Osterix and Runx2 in the PCL/SrC20 fibers. Thus, incorporation of nSrCO(3) in polymer scaffolds is a promising strategy for bone tissue engineering as an alternative to the use of labile growth factors to impart bioactivity to polymer scaffolds. (C) 2016 Elsevier B.V. All rights reserved.