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TheScientificWorldJOURNAL
Volume 8 (2008), Pages 1269-1279
http://dx.doi.org/10.1100/tsw.2008.163
Research Article

Influence of Poly(L-Lactic Acid) Nanofibers and BMP-2–Containing Poly(L-Lactic Acid) Nanofibers on Growth and Osteogenic Differentiation of Human Mesenchymal Stem Cells

1Department of Orthopedics, University Hospital of Marburg, D-35043 Marburg, Baldingerstraße, Germany
2Department of Chemistry, University of Marburg, D-35032 Marburg, Hans-Meerwein-Straße, Germany
3Department of Orthopedics, Sankt-Elisabeth-Hospital Gütersloh, D-33332 Gütersloh, Kattenstroth 103, Germany

Received 5 October 2008; Revised 9 December 2008; Accepted 17 December 2008

Academic Editor: Martin Goette

Copyright © 2008 Markus D. Schofer et al.

Abstract

The aim of this study was to characterize synthetic poly-(L-lactic acid) (PLLA) nanofibers concerning their ability to promote growth and osteogenic differentiation of stem cells in vitro, as well as to test their suitability as a carrier system for growth factors. Fiber matrices composed of PLLA or BMP-2–incorporated PLLA were seeded with human mesenchymal stem cells and cultivated over a period of 22 days under growth and osteoinductive conditions, and analyzed during the course of culture, with respect to gene expression of alkaline phosphatase (ALP), osteocalcin (OC), and collagen I (COL-I). Furthermore, COL-I and OC deposition, as well as cell densities and proliferation, were analyzed using fluorescence microscopy. Although the presence of nanofibers diminished the dexamethasone-induced proliferation, there were no differences in cell densities or deposition of either COL-I or OC after 22 days of culture. The gene expression of ALP, OC, and COL-I decreased in the initial phase of cell cultivation on PLLA nanofibers as compared to cover slip control, but normalized during the course of cultivation. The initial down-regulation was not observed when BMP-2 was directly incorporated into PLLA nanofibers by electrospinning, indicating that growth factors like BMP-2 might survive the spinning process in a bioactive form.