title: Ion-exchange polymer nanofibers for enhanced osteogenic differentiation of stem cells and ectopic bone formation.
abstract: Nanofibrous scaffolds with specific modifications have shown promising potential for bone tissue engineering applications. In the present study, poly(ether sulfone) (PES) and sulfonated PES (SPES) nanofibers were fabricated via electrospinning. Calcium ions were then incorporated in SPES by immersion in a Ca(OH)2 solution. The calcium-ion-exchanged SPES (Ca-SPES), PES, and SPES nanofibers were characterized and then evaluated for their osteogenic capacity: both in vitro using stem cell culture and in vivo after subcutaneous implantation in mice. After 7 days of immersion in simulated body fluid, the formation of an apatite layer was only observed on Ca-SPES nanofibers. According to the MTT results, an increasing stem cell population was detected on all scaffolds during the period of study. Using real-time reverse transcriptase-polymerase chain reaction, alkaline phosphatase activity, and calcium content assays, it was demonstrated that the osteogenic differentiation of stem cells was higher on Ca-SPES scaffolds in comparison with PES and SPES nanofibers. Interestingly, Ca-SPES scaffolds were shown to induce ectopic bone formation after 12 weeks of subcutaneous implantation in mice. This was confirmed by mineralization and the production of collagen fibers using van Kossa and Masson's trichrome staining, respectively. Taken together, it was demonstrated that the incorporation of calcium ions into the ion-exchange nanofibrous scaffolds not only gives them the ability to enhance osteogenic differentiation of stem cells in vitro but also to induce ectopic bone formation in vivo.
authors: Department of Polymer Engineering and Color Technology, Amirkabir University of Technology , Tehran, Iran.
authors: Iman
authors: I
authors: Shabani
authors: Vahid
authors: V
authors: Haddadi-Asl
authors: Masoud
authors: M
authors: Soleimani
authors: Ehsan
authors: E
authors: Seyedjafari
authors: Seyed Mahmoud
authors: SM
authors: Hashemi
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D001483:Base Sequence; D001846:Bone Development; D001842:Bone and Bones / Q000166:cytology* / Q000201:enzymology; D002454:Cell Differentiation; D002478:Cells, Cultured; D017931:DNA Primers; D006801:Humans; D007475:Ion Exchange Resins; D008855:Microscopy, Electron, Scanning; D057139:Nanofibers; D011108:Polymers / Q000737:chemistry*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017550:Spectroscopy, Fourier Transform Infrared; D013234:Stem Cells / Q000166:cytology*; D054457:Tissue Scaffolds
chemical_list: D017931:DNA Primers; D007475:Ion Exchange Resins; D011108:Polymers; D000469:Alkaline Phosphatase