delivery of platelet-derived growth factor as a chemotactic factor for mesenchymal stem cells by bone-mimetic electrospun scaffolds交付血小板源生长因子作为间充质干细胞的趋化因子bone-mimetic实际上电纺支架.pdfVIP

Delivery of Platelet-Derived Growth Factor as a Chemotactic Factor for Mesenchymal Stem Cells by Bone-Mimetic Electrospun Scaffolds 1 1 1,2 Matthew C. Phipps , Yuanyuan Xu , Susan L. Bellis * 1 Department of Physiology and Biophysics, University of Alabama at Birmingham, Birmingham, Alabama, United States of America, 2 Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, Alabama, United States of America Abstract The recruitment of mesenchymal stem cells (MSCs) is a vital step in the bone healing process, and hence the functionalization of osteogenic biomaterials with chemotactic factors constitutes an important effort in the tissue engineering field. Previously we determined that bone-mimetic electrospun scaffolds composed of polycaprolactone, collagen I and nanohydroxyapatite (PCL/col/HA) supported greater MSC adhesion, proliferation and activation of integrin- related signaling cascades than scaffolds composed of PCL or collagen I alone. In the current study we investigated the capacity of bone-mimetic scaffolds to serve as carriers for delivery of an MSC chemotactic factor. In initial studies, we compared MSC chemotaxis toward a variety of molecules including PDGF-AB, PDGF-BB, BMP2, and a mixture of the chemokines SDF-1a, CXCL16, MIP-1a, MIP-1b, and RANTES. Transwell migration assays indicated that, of these factors, PDGF- BB was the most effective in stimulating MSC migration. We next evaluated the capacity of PCL/col/HA scaffolds, compared with PCL scaffolds, to adsorb and release PDGF-BB. We found that significantly more PDGF- BB was adsorbed to, and subsequently released from, PCL/c