Modulation of Osteogenic Differentiation of Human Mesenchymal Stem Cells by Poly[(L-lactide)-co-(epsilon-caprolactone)]/Gelatin Nanofibers

Abstract

Developing biomaterial scaffolds to elicit specific cell responses is important in many tissue engineering applications. We hypothesized that the chemical composition of the scaffold may be a key determinant for the effective induction of differentiation in human mesenchymal stem cells (hMSCs). In this study, electrospun nanofibers with different chemical compositions were fabricated using poly[(L-lactide)-co-(epsilon-caprolactone)] (PLCL) and gelatin. Scanning electron microscopy (SEM) images showed a randomly arranged structure of nanofibers with diameters ranging from 400 nm to 600 nm. The incorporation of gelatin in the nanofibers stimulated the adhesion and osteogenic differentiation of hMSCs. For example, the well-stretched and polygonal morphology of hMSCs was observed on the gelatin-containing nanofibers, while the cells cultured on the PLCL nanofibers were contracted. The DNA content and alkaline phosphatase activity were significantly increased on the PLCL/gelatin blended nanofibers. Expression of osteogenic genes including alkaline phosphatase (ALP), osteocalcin (OCN), and collagen type I-alpha 2 (Col I-alpha 2) were also upregulated in cells cultured on nanofibers with gelatin. Mineralization of hMSCs was analyzed by von Kossa staining and the amount of calcium was significantly enhanced on the gelatin-incorporated nanofibers. These results suggest that the chemical composition of the underlying scaffolds play a key role in regulating the osteogenic differentiation of hMSCs.