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ÜNAL YILDIRIM, SEMRA

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ÜNAL YILDIRIM

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2019 - 201912020 - 20213
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    Design and characterization of polycaprolactone-gelatin-graphene oxide scaffolds for drug influence on glioblastoma cells
    (PERGAMON-ELSEVIER SCIENCE LTD, 2019) ATASOY, BESTE MELEK; Unal, Semra; Arslan, Sema; Gokce, Tilbe; Atasoy, Beste Melek; Karademir, Betul; Oktar, Faik Nuzhet; Gunduz, Oguzhan
    Three-dimensional (3D) scaffolds that mimic in vivo tumor microenvironments can be used to study tumor response to anticancer treatments, since most preclinical combination treatment strategy for anti-glioma were evaluated with traditional 2D cell culture. In this research, the nanofiber scaffolds of polycaprolactone (PCL) containing gelatin (Gel) nano/microparticles coated with different concentrations of graphene oxide (GO) and were successfully produced by combining electrospinning and electrospraying techniques. Scanning electron microscope (SEM), Fourier-transform infrared (FT-IR) spectroscopy and mechanical testing were used to characterize the structure and properties of the composites. The results show that gelatin and graphene particles can be well dispersed in the polycaprolactone nanofiber matrix by using the combination technique of electrospinning and electrospraying. The presence of 1 wt% graphene oxide increased mechanical strength of PCL/Gel scaffold and was found to be well consistent with the drug treatments (temozolomide and bortezomib) and radiotherapy by not showing additional toxicity.
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    Glioblastoma cell adhesion properties through bacterial cellulose nanocrystals in polycaprolactone/gelatin electrospun nanofibers
    (ELSEVIER SCI LTD, 2020) YILMAZ, BETÜL; Unal, Semra; Arslan, Sema; Yilmaz, Betul Karademir; Kazan, Dilek; Oktar, Faik Nuzhet; Gunduz, Oguzhan
    Glioblastoma (GBM), the most common and extremely lethal type of brain tumor, is resistant to treatment and shows high recurrence rates. In the last decades, it is indicated that standard two-dimensional (2D) cell culture is inadequate to improve new therapeutic strategies and drug development. Hence, well-mimicked three-dimensional (3D) tumor platforms are needed to bridge the gap between in vitro and in vivo cancer models. In this study, bacterial cellulose nano-crystal (BCNC) containing polycaprolactone (PCL) /gelatin (Gel) nanofibrous composite scaffolds were successfully fabricated by electrospinning for mimicking the extracellular matrix of GBM tumor. The fiber diameters in the nanofibrous matrix were increased with an increased concentration of BCNC. Moreover, fiber morphology changed from the smooth formation to the beaded formation by increasing the concentration of the BCNC suspension. In-vitro biocompatibilities of nanofibrous scaffolds were tested with U251 MG glioblastoma cells and improved cell adhesion and proliferation was compared with PCL/Gel. PCL/Gel/BCNC were found suitable for enhancing axon growth and elongation supporting communication between tumor cells and the microenvironment, triggering the process of tumor recurrence. Based on these results, PCL/Gel/BCNC composite scaffolds are a good candidate for biomimetic GBM tumor platform.
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    Development of a nonwetting coating for packaging substrate surfaces using a novel and easy to implement method
    (WALTER DE GRUYTER GMBH, 2021) UZUN, MUHAMMET; Soez, Cagla Kosak; Ozomay, Zafer; Unal, Semra; Uzun, Muhammet; Sonmez, Sinan
    This study is about preparing different paper substrates with chemically stable hydrophobic and superhydrophobic surface coatings through spraying a mixture of poly(dimethylsiloxane) (PDMS) and inorganic particles. The method is easy to implement, reproducible and requires inexpensive starting materials. Non-colored and colored types of (i) raw paper (UC), (ii) glossy coated paper (GC) and (iii) matte coated paper (MC) surfaces were selected for surface modification through the coating application. Both water-based ink (WB) and solvent-based ink (SB) formulations were used to dye substrate surfaces. Investigations including surface wetting, optical and physical properties of the coated paper substrates revealed that the coating application method proposed is a promising lacquer alternative for packaging purposes.
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    Production and characterization of bacterial cellulose scaffold and its modification with hyaluronic acid and gelatin for glioblastoma cell culture
    (SPRINGER, 2021) YILMAZ, BETÜL; Unal, Semra; Arslan, Sema; Yilmaz, Betul Karademir; Oktar, Faik Nuzhet; Sengil, Ahmet Zeki; Gunduz, Oguzhan
    Three-dimensional (3D) in vitro cell culture models have recently gained increasing interest in predicting the response of anticancer drugs. In this study first, we tried to obtain a novel hyaluronic acid (HA)/gelatin (Gel) modified bacterial cellulose (BC) composite scaffolds by in situ fermentation method. Morphological and chemical structures, wettability, and thermal stability of scaffolds were evaluated. In particular, the human glioblastoma (GBM) cancer cell line (U251) was seeded into BC/HA/Gel scaffolds to evaluate their potential as in vitro 3D cancer cell culture. MTT proliferation assay, scanning electron microscopy, and confocal microscopy were utilised to determine cell proliferation, morphology and adhesion. The results suggest that our hyaluronic acid and gelatin modified bacterial cellulose scaffold is promising to be used as in vitro 3D culture of GBM cells and may be used to predict treatment response or reactions of new therapeutics.