Browsing by Subject "Replication techniques"

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    In vivo evaluation of cerium, gallium and vanadium-doped borate-based bioactive glass scaffolds using rat subcutaneous implantation model
    (Elsevier Ltd, 2016) Deliormanlı A.M.; Seda Vatansever H.; Yesil H.; Özdal-Kurt F.
    The main objective of this study was to evaluate the cerium, gallium and vanadium-containing bioactive borate glass scaffolds for soft tissue applications and determine the potential toxicity of these scaffolds on the adjacent tissues. The effects of the cerium, gallium and vanadium substitution on the soft tissue ingrowth and angiogenesis in porous borate based bioactive glass scaffolds were investigated using rat subcutaneous implantation model. For this purpose, bioactive borate glass powders containing therapeutic ions were prepared by melt-cast method and subsequently scaffolds were fabricated using polymer foam replication technique. The scaffolds were implanted subcutaneously for 4 weeks in Sprague Dawley rats. Bare borate glass scaffolds with the same microstructure were used as the control. Histology was used to evaluate tissue ingrowth and blood vessel formation in the implants. Additionally, the antibacterial activities of cerium, gallium and vanadium containing porous bioactive glass scaffolds were investigated in vitro by a zone inhibition method. Results revealed that addition of cerium ions to the borate glass network caused an increase in blood vessel formation. On the other hand, a decrease was obtained in angiogenesis in gallium and vanadium-containing glasses. All of the scaffolds prepared in the study did not show any antibacterial activity towards Escherichia coli and Staphylococcus aureus. © 2016 Elsevier Ltd and Techna Group S.r.l.
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    Electrically conductive borate-based bioactive glass scaffolds for bone tissue engineering applications
    (SAGE Publications Ltd, 2017) Turk M.; Deliormanll A.M.
    In this study, electrically conductive, borate-based, porous 13-93B3 bioactive glass composite scaffolds were prepared using a polymer foam replication technique. For this purpose, a slurry containing 40 vol% glass particles and 0-10 wt% graphene nanoplatelets was prepared by dispersing the particles in ethanol in the presence of ethyl cellulose. Composite scaffolds were subjected to a controlled heat treatment, in air atmosphere, to decompose the foam and sinter the glass particles into a dense network. It was found that the applied heat treatment did not influence the structure of graphene in the glass network. Graphene additions did not negatively affect the mechanical properties and enhanced the electrical conductivity of the glass scaffolds. In X-ray diffraction analysis, the crystalline peak corresponding to hydroxyapatite was observed in all the samples suggesting that all of the samples were bioactive after 30 days of immersion in simulated body fluid. However, Fourier transform infrared spectroscopy analysis and scanning electron microscope observations revealed that hydroxyapatite formation rate decreased with increasing graphene concentration especially for samples treated in simulated body fluid for shorter times. Based on the cytotoxicity assay findings, the MC3T3-E1 cell growth was significantly inhibited by the scaffolds containing higher amount of graphene compared to bare glass scaffolds. Best performance was obtained for 5 wt% graphene which yielded an enhancement of electrical conductivity with moderate cellular response and in vitro hydroxyapatite forming ability. The study revealed that the electrically conductive 13-93B3 graphene scaffolds are promising candidates for bone tissue engineering applications. © The Author(s) 2017.