Curcumin eluting nanofibers augment osteogenesis toward phytochemical based bone tissue engineering

Curcumin is a phenolic compound isolated from Curcuma longa that is known to exhibit wide ranging biological activity including potential benefits for bone growth. The aim of this work was to engineer curcumin eluting tissue scaffolds and investigate their potential use in bone tissue regeneration. We prepared curcumin loaded poly(e-caprolactone) (PCL) nanofibers by electrospinning. Morphological characterization of the nanofibers revealed that the average diameter of neat fibers and that of fibers with 1 wt% and 5 wt% curcumin is 840 +/- 130 nm, 827 +/- 129 nm and 680 +/- 110 nm, respectively. Fourier transformation infrared spectroscopy and H-1 nuclear magnetic resonance confirmed the successful loading of the drug in fibers. In aqueous medium, the fibers released approximate to 18% of the encapsulated drug in 3 d and approximate to 60% in 9 d. The cell response to the curcumin loaded nanofibers was assessed using MC3T3-E1 pre-osteoblasts. Cell proliferation was moderated with increased loading of curcumin and was 50% lower on the fibers containing 5% curcumin at day 10 than the control fibers. Osteogenesis was confirmed by assaying the expression of alkaline phosphatase and staining of mineral deposits by Alizarin red stain, which were both markedly higher for 1% curcumin compared to neat polymer but lower for 5% curcumin. Mineral deposition was also confirmed chemically by Fourier transform infrared spectroscopy. These results were corroborated by increased gene and protein expression of known osteogenic markers in 1% curcumin. Thus, controlled release of curcumin from polymer scaffolds is a promising strategy for bone tissue regeneration.