Person: EKREN, NAZMİ
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EKREN
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NAZMİ
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Publication Metadata only Patch-Based Technology for Corneal Microbial Keratitis(Springer, 2020) AKSU, MEHMET BURAK; Ulag S., Ilhan E., Aksu B., Sengor M., Ekren N., Kilic O., Gunduz O.Corneal opacities, which happened mainly due to microbial keratitis, are the fourth cause of blindness worldwide. Antimicrobial therapy is an alternative solution for microbial keratitis caused by Staphylococcus aureus and Pseudomonas Aeruginosa. The aim of this study, to develop patches for the treatment of corneal keratitis which caused significant corneal blindness by using electrospinning method. Polyvinyl-alcohol (PVA) patches with Gelatine (GEL) studied in various ratios. Different amounts of gelatine added to PVA to resemble the collagen fibril structure of the cornea. To enable the patches to the antimicrobial effect against the bacterias, the special plant extract was used. The produced corneal patches were examined separately for chemical, morphological, and antimicrobial properties. Scanning electron microscope (SEM), Fourier-transform infrared (FT-IR) spectroscopy were performed to observe the surface morphology and chemical structure of the patches, respectively. © Springer Nature Switzerland AG 2020.Publication Metadata only Recent developments and characterization techniques in 3D printing of corneal stroma tissue(WILEY, 2021) ŞENGÖR, MUSTAFA; Ulag, Songul; Uysal, Ebru; Bedir, Tuba; Sengor, Mustafa; Ekren, Nazmi; Ustundag, Cem Bulent; Midha, Swati; Kalaskar, Deepak M.; Gunduz, OguzhanCorneal stroma has a significant function in normal visual function. The corneal stroma is vulnerable because of being the thickest part of the cornea, as it can be affected easily by infections or injuries. Any problems on corneal stroma can result in blindness. Donor shortage for corneal transplantation is one of the main issues in corneal transplantation. To address this issue, the corneal tissue engineering focuses on replacing injured tissues and repairing normal functions. Currently, there are no available, engineered corneal tissues for widely accepted routine clinical treatment, but new emerging 3D printing applications are being recognized as a promising option. Recent in vitro researches revealed that the biocompatibility and regeneration possessions of 3D-printed hydrogels outperformed conventional tissue engineering approaches. The goal of this review is to highlight the current developments in the characterization of 3D cell-free and bioprinted hydrogels.Publication Open Access 3D printing of PVA/hexagonal boron nitride/bacterial cellulose composite scaffolds for bone tissue engineering(ELSEVIER SCI LTD, 2020-11) ŞENGÖR, MUSTAFA; Aki, Deniz; Ulag, Songul; Unal, Semra; Sengor, Mustafa; Ekren, Nazmi; Lin, Chi-Chang; Yilmazer, Hakan; Ustundag, Cem Bulent; Kalaskar, Deepak M.; Gunduz, OguzhanIn this study, a novel Polyvinyl Alcohol (PVA)/Hexagonal Boron Nitride (hBN)/Bacterial Cellulose (BC) composite, bone tissue scaffolds were fabricated using 3D printing technology. The printed scaffolds were characterized by fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), tensile testing, swelling behaviour, differential scanning calorimetry (DSC), and in vitro cell culture assay. Results demonstrated that bacterial cellulose addition affected the characteristic properties of the blends. Morphological studies revealed the homogenous dispersion of the bacterial cellulose within the 12 wt%PVA/0.25 wt%hBN matrix. Tensile strength of the scaffolds was decreased with the incorporation of BC and 12 wt%PVA/0.25 wt%hBN/0.5 wt%BC had the highest elongation at break value (93%). A significant increase in human osteoblast cell viability on 3D scaffolds was observed for 12 wt%PVA/0.25 wt%hBN/0.5 wt%BC. Cell morphology on composite scaffolds showed that bacterial cellulose doped scaffolds appeared to adhere to the cells. The present work deduced that bacterial cellulose doped 3D printed scaffolds with well-defined porous structures have considerable potential as a suitable tissue scaffold for bone tissue engineering (BTE). (c) 2020 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).Publication Metadata only A novel approach to treat the Thiel-Behnke corneal dystrophy using 3D printed honeycomb-shaped polymethylmethacrylate (PMMA)/Vancomycin (VAN) scaffolds(Elsevier B.V., 2021) ŞAHİN, ALİ; Ulag S., Sahin A., Guncu M.M., Aksu B., Ekren N., Sengor M., Kalaskar D.M., Gunduz O.Thiel-Behnke corneal dystrophy, or honeycomb corneal dystrophy, is an autosomal dominant corneal disorder. Tissue engineering can be a novel approach to regenerate this dystrophy. In this study, the honeycomb geometry of the dystrophy mimicked with a 3D printing technology, and 40% PMMA, 40% PMMA/(0.1, 0.5, 2, and 10)% VAN scaffolds were fabricated with honeycomb geometry. As a result of the biocompatibility test with mesenchymal stem cells (MSCs), it can be said that cells on the scaffolds showed high viability and proliferation for all incubation periods. According to the antibacterial activity results, the 40% PMMA/10% VAN showed antibacterial activity against S. aureous. Mechanical results reported that with the addition of VAN into the 40% PMMA, the tensile strength value increased up to 2% VAN amount. The swelling behaviours of the scaffolds were examined in vitro, and found that the swelling rate increased with a high VAN amount. The release of VAN from the scaffolds showed sustained release behaviour, and it took 13 days to be released entirely from the scaffolds. © 2021 Elsevier B.V.Publication Metadata only Gel-Inks for 3D printing in corneal tissue engineering(Springer, 2021-01-01) ŞENGÖR, MUSTAFA; EKREN, NAZMİ; GÜNDÜZ, OĞUZHAN; Ulağ S., Cesur S., DOĞAN E., ŞENGÖR M., EKREN N., ÜSTÜNDAĞ C. B., GÜNDÜZ O.