Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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  • Article
    Citation - WoS: 25
    Citation - Scopus: 27
    Osteogenic Differentiation of Mesenchymal Stem Cells on Random and Aligned Pan/Ppy Nanofibrous Scaffolds
    (SAGE Publications, 2019) Selamet, Yusuf; İnce Yardımcı, Atike; Baskan, Öznur; Yılmaz, Selahattin; Meşe, Gülistan; Özçivici, Engin
    The aim of this study was to develop random and aligned polyacrilonitrile (PAN)/polypyrrole (PPy) nanofibrous scaffolds by electrospinning technique for osteogenic differentiation of mesenchymal stem cells. Nanofibers were fabricated successfully as straight, smooth, and free from bead formation. The average diameter of random and aligned nanofibers was 268(+/- 49) nm and 225(+/- 72) nm, respectively. Alignment process increased the tensile strength of nanofibers 3.9-fold, while the tensile strain of nanofibers decreased by 78%. PAN/PPy nanofibers were hydrophilic with the contact angle value of about 32 degrees and alignment did not affect the contact angle value. Random and aligned PAN/PPy nanofibers were investigated as a scaffold material for osteogenic differentiation of D1 ORL UVA mouse bone marrow mesenchymal stem cells. Cells were able to attach and grow on nanofibers confirmed by cell viability results. Stem cells that were cultured with osteogenic induction were able to mineralize on electrospun nanofibers based on alizarin red and Von Kossa dye staining. For aligned PPy nanofibers, mineralization occurred in the fiber alignment direction. Consequently, PAN/PPy nanofibrous mats in both random and aligned forms would be potential candidates for bone tissue engineering.
  • Article
    Citation - WoS: 8
    Citation - Scopus: 11
    Application of Low Intensity Mechanical Vibrations for Bone Tissue Maintenance and Regeneration
    (TÜBİTAK, 2016) Ölçüm, Melis; Baskan, Öznur; Karadaş, Özge; Özçivici, Engin
    Physical exercise is beneficial for bone tissue health, yet its usage is limited for preventing osteoporosis. Even though natural for the bone tissue from development to homeostasis, mechanical loads present with a multitude of physical parameters, including amplitude, duration, frequency, and distribution. Utilizing the most beneficial parameters of mechanical loads may potentiate a nonpharmaceutical tool for biotechnology to prevent and treat bone loss related to aging, bedrest, sedentary lifestyles, weightlessness, and other diseases. Low intensity vibrations (LIVs) consist of mechanical loads with amplitudes smaller than loads prescribed by habitual activity, with a higher frequency. In this review, literature covering LIV signal application on bone tissue and cellular and molecular level is presented. Studies indicate that LIV signals are safe, anabolic, and anticatabolic for skeletal tissue and are of great significance in regenerative medicine applications.
  • Article
    Citation - WoS: 26
    Citation - Scopus: 32
    Low-Intensity Vibrations Normalize Adipogenesis-Induced Morphological and Molecular Changes of Adult Mesenchymal Stem Cells
    (SAGE Publications Inc., 2017) Baskan, Öznur; Meşe, Gülistan; Özçivici, Engin
    Bone marrow mesenchymal stem cells that are committed to adipogenesis were exposed daily to high-frequency low-intensity mechanical vibrations to understand molecular, morphological and ultrastructural adaptations to mechanical signals during adipogenesis. D1-ORL-UVA mouse bone marrow mesenchymal stem cells were cultured with either growth or adipogenic medium for 1 week. Low-intensity vibration signals (15 min/day, 90 Hz, 0.1 g) were applied to one group of adipogenic cells, while the other adipogenic group served as a sham control. Cellular viability, lipid accumulation, ultrastructure and morphology were determined with MTT, Oil-Red-O staining, phalloidin staining and atomic force microscopy. Semiquantitative reverse transcription polymerase chain reaction showed expression profile of the genes responsible for adipogenesis and ultrastructure of cells. Low-intensity vibration signals increased viability of the cells in adipogenic culture that was reduced significantly compared to quiescent controls. Low-intensity vibration signals also normalized the effects of adipogenic condition on cell morphology, including area, perimeter, circularization and actin cytoskeleton. Furthermore, low-intensity vibration signals reduced the expression of some adipogenic markers significantly. Mesenchymal stem cells are sensitive and responsive to mechanical loads, but debilitating conditions such as aging or obesity may steer mesenchymal stem cells toward adipogenesis. Here, daily application of low-intensity vibration signals partially neutralized the effects of adipogenic induction on mesenchymal stem cells, suggesting that these signals may provide an alternative and/or complementary option to reduce fat deposition.