Araştırma Çıktıları

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Author: search.filters.author.Hasirci, VasifSubject: search.filters.subject.bone tissue engineering

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    Evaluating Oxygen Tensions Related to Bone Marrow and Matrix for MSC Differentiation in 2D and 3D Biomimetic Lamellar Scaffolds
    (MDPI, 2021-01-01) Sayin, Esen; Baran, Erkan Turker; Elsheikh, Ahmed; Mudera, Vivek; Cheema, Umber; Hasirci, Vasif
    The physiological O-2 microenvironment of mesenchymal stem cells (MSCs) and osteoblasts and the dimensionality of a substrate are known to be important in regulating cell phenotype and function. By providing the physiologically normoxic environments of bone marrow (5\%) and matrix (12\%), we assessed their potential to maintain stemness, induce osteogenic differentiation, and enhance the material properties in the micropatterned collagen/silk fibroin scaffolds that were produced in 2D or 3D. Expression of osterix (OSX) and vascular endothelial growth factor A (VEGFA) was significantly enhanced in the 3D scaffold in all oxygen environments. At 21\% O-2, OSX and VEGFA expressions in the 3D scaffold were respectively 13,200 and 270 times higher than those of the 2D scaffold. Markers for assessing stemness were significantly more pronounced on tissue culture polystyrene and 2D scaffold incubated at 5\% O-2. At 21\% O-2, we measured significant increases in ultimate tensile strength (p < 0.0001) and Young's modulus (p = 0.003) of the 3D scaffold compared to the 2D scaffold, whilst 5\% O-2 hindered the positive effect of cell seeding on tensile strength. In conclusion, we demonstrated that the 3D culture of MSCs in collagen/silk fibroin scaffolds provided biomimetic cues for bone progenitor cells toward differentiation and enhanced the tensile mechanical properties.
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    Collagen scaffolds with in situ-grown calcium phosphate for osteogenic differentiation of Wharton's jelly and menstrual blood stem cells
    (WILEY, 2014-01-01) Karadas, Ozge; Yucel, Deniz; Kenar, Halime; Kose, Gamze Torun; Hasirci, Vasif
    The aim of this research was to investigate the osteogenic differentiation potential of non-invasively obtained human stem cells on collagen nanocomposite scaffolds with in situ-grown calcium phosphate crystals. The foams had 70\% porosity and pore sizes varying in the range 50-200 mu m. The elastic modulus and compressive strength of the calcium phosphate containing collagen scaffolds were determined to be 234.5 kPa and 127.1 kPa, respectively, prior to in vitro studies. Mesenchymal stem cells (MSCs) obtained from Wharton's jelly and menstrual blood were seeded on the collagen scaffolds and proliferation and osteogenic differentiation capacities of these cells from two different sources were compared. The cells on the composite scaffold showed the highest alkaline phosphatase activity compared to the controls, cells on tissue culture polystyrene and cells on collagen scaffolds without in situ-formed calcium phosphate. MSCs isolated from both Wharton's jelly and menstrual blood showed a significant level of osteogenic activity, but those from Wharton's jelly performed better. In this study it was shown that collagen nanocomposite scaffolds seeded with cells obtained non-invasively from human tissues could represent a potential construct to be used in bone tissue engineering. Copyright (C) 2012 John Wiley \& Sons, Ltd.