Browsing by Author "Morçimen, ZG"

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    Surface Area of Graphene Governs Its Neurotoxicity
    Tasdemir, S; Morçimen, ZG; Dogan, AA; Görgün, C; Sendemir, A
    Due to their uniquephysicochemical properties, graphene and itsderivatives are widely exploited for biomedical applications. It hasbeen shown that graphene may exert different degrees of toxicity inin vivo or in vitro models when administered via different routesand penetrated through physiological barriers, subsequently beingdistributed within tissues or located within cells. In this study,in vitro neurotoxicity of graphene with different surface areas (150and 750 m(2)/g) was examined on dopaminergic neuron modelcells. SH-SY5Y cells were treated with graphene possessing two differentsurface areas (150 and 750 m(2)/g) in different concentrationsbetween 400 and 3.125 mu g/mL, and the cytotoxic and genotoxiceffects were investigated. Both sizes of graphene have shown increasedcell viability in decreasing concentrations. Cell damage increasedwith higher surface area. Lactate dehydrogenase (LDH) results haveconcluded that the viability loss of the cells is not through membranedamage. Neither of the two graphene types showed damage through lipidperoxidation (MDA) oxidative stress pathway. Glutathione (GSH) valuesincreased within the first 24 and 48 h for both types of graphene.This increase suggests that graphene has an antioxidant effect onthe SH-SY5Y model neurons. Comet analysis shows that graphene doesnot show genotoxicity on either surface area. Although there are manystudies on graphene and its derivatives on their use with differentcells in the literature, there are conflicting results in these studies,and most of the literature is focused on graphene oxide. Among thesestudies, no study examining the effect of graphene surface areas onthe cell was found. Our study contributes to the literature in termsof examining the cytotoxic and genotoxic behavior of graphene withdifferent surface areas.
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    Design of chemobrionic and biochemobrionic scaffolds for bone tissue engineering
    Guler, BA; Morçimen, ZG; Tasdemir, S; Demirel, Z; Turunç, E; Sendemir, A; Imamoglu, E
    Chemobrionic systems have attracted great attention in material science for development of novel biomimetic materials. This study aims to design a new bioactive material by integrating biosilica into chemobrionic structure, which will be called biochemobrionic, and to comparatively investigate the use of both chemobrionic and biochemobrionic materials as bone scaffolds. Biosilica, isolated from Amphora sp. diatom, was integrated into chemobrionic structure, and a comprehensive set of analysis was conducted to evaluate their morphological, chemical, mechanical, thermal, and biodegradation properties. Then, the effects of both scaffolds on cell biocompatibility and osteogenic differentiation capacity were assessed. Cells attached to the scaffolds, spread out, and covered the entire surface, indicating the absence of cytotoxicity. Biochemobrionic scaffold exhibited a higher level of mineralization and bone formation than the chemobrionic structure due to the osteogenic activity of biosilica. These results present a comprehensive and pioneering understanding of the potential of (bio)chemobrionics for bone regeneration.