Person: EKREN, NAZMİ
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EKREN
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NAZMİ
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Publication Open Access Bioinspired scaffold induced regeneration of neural tissue(PERGAMON-ELSEVIER SCIENCE LTD, 2019-05) EKREN, NAZMİ; Altun, Esra; Aydogdu, Mehmet O.; Togay, Sine O.; Sengil, Ahmet Z.; Ekren, Nazmi; Haskoylu, Merve E.; Oner, Ebru T.; Altuncu, Nese A.; Ozturk, Gurkan; Crabbe-Mann, Maryam; Ahmed, Jubair; Gunduz, Oguzhan; Edirisinghe, MohanIn the last decade, nerve tissue engineering has attracted much attention due to the incapability of self-regeneration. Nerve tissue regeneration is mainly based on scaffold induced nanofibrous structures using both bio and synthetic polymers. The produced nanofibrous scaffolds have to be similar to the natural extracellular matrix and should provide an appropriate environment for cells to attach onto. Nanofibrous scaffolds can support or regenerate cells of tissue. Electrospinning is an ideal method for producing the nanofibrous scaffolds. In this study, Bacterial cellulose (BC)/Poly (epsilon-caprolactone) (PCL) blend nanofibrous scaffolds were successfully prepared by electrospinning for nerve tissue induced repair. The produced nanofibrous scaffolds contain well defined interconnected nanofiber networks with hollow micro/nanobeads. Firstly, in-vitro biocompatibilities of nanofibrous scaffolds were tested with L2929 murine fibroblasts and improved cell adhesion and proliferation was observed with polymer blends compared with PCL only. The primary cell culture was performed with dorsal root ganglia (DRG) cells on nanofibrous samples and the samples were found suitable for enhancing neural growth and neurite outgrowth. Based on these results, the BC/PCL (50:50 wt.%) nanofibrous scaffolds exhibited nerve-like branching and are excellent candidate for potential biomimetic applications in nerve tissue engineering regeneration.Publication Metadata only Production and Characterization of Antimicrobial Electrospun Nanofibers Containing Polyurethane, Zirconium Oxide and Zeolite(SPRINGER, 2018) OKTAR, FAİK NÜZHET; Aydogdu, Mehmet Onur; Oprea, Alexandra Elena; Trusca, Roxana; Surdu, Adrian Vasile; Ficai, Anton; Holban, Alina Maria; Iordache, Florin; Paduraru, Andrei Viorel; Filip, Diana Georgiana; Altun, Esra; Ekren, Nazmi; Oktar, Faik Nuzhet; Gunduz, OguzhanIn this study, electrospinning technique has been utilized to prepare composite nanofiber mats of polyurethane (PU)/zirconium dioxide (ZrO2) and PU/zeolite, consisted by antimicrobial properties. Tensile strength measurement test was performed for the mechanical analysis of the nanofibers. Scanning electron microscopy (SEM) were performed for displaying the morphological features of the fiber structure. XRD tests were performed for revealing the chemical structure. Antimicrobial tests were also performed to display antimicrobial effects of the produced materials. In vitro test was also performed to determine cytotoxicity and biocompatibility. The present PU/ZrO2 and PU/zeolite composite nanofibers resulted with improved mechanical properties and good antimicrobial properties against either their pure forms or other studies. Cell proliferation and viability also increased significantly with increase in zeolite and ZrO2 ratio. It is concluded that this composition provides a novel alternative as an antimicrobial material which can be suitable as a wound dressing or a coating material for various healthcare engineering applications.Publication Metadata only Production of the biomimetic small diameter blood vessels for cardiovascular tissue engineering(TAYLOR & FRANCIS AS, 2019) TOKSOY ÖNER, EBRU; Aydogdu, Mehmet Onur; Chou, Joshua; Altun, Esra; Ekren, Nazmi; Cakmak, Selami; Eroglu, Mehmet; Osman, Asila A.; Kutlu, Ozlem; Oner, Ebru Toksoy; Avsar, Gulben; Oktar, Faik Nuzhet; Yilmaz, Ismail; Gunduz, OguzhanA novel biomimetic vascular graft scaffolds were produced by electrospinning method with the most superior characteristics to be a proper biomimetic small diameter blood vessel using Polycaprolactone(PCL), Ethyl Cellulose(EC) and Collagen Type-1 were used to create the most convenient synergy of a natural and synthetic polymer to achieve similarity to native small diameter blood vessels. Scanning Electron Microscopy(SEM), Fourier Transform Infrared Spectroscopy(FTIR), Differential Scanning Calorimetry Analysis(DSC), tensile measurement tests, and in-vitro and in-vivo applications were performed. Results indicated significant properties such as having 39.33 nm minimum, 104.98 nm average fiber diameter, 3.2 MPa young modulus and 135% relative cell viability. [GRAPHICS] .Publication Open Access Starch/PCL composite nanofibers by co-axial electrospinning technique for biomedical applications(BMC, 2017-12) OKTAR, FAİK NÜZHET; Komur, B.; Bayrak, F.; Ekren, N.; Eroglu, M. S.; Oktar, F. N.; Sinirlioglu, Z. A.; Yucel, S.; Guler, O.; Gunduz, O.Background: In this study, starch and polycaprolactone (PCL), composite nanofibers were fabricated by co- axial needle electrospinning technique. Processing parameters such as polymer concentration, flow rate and voltage had a marked influence on the composite fiber diameter. Fourier transform infrared spectroscopy, scanning electron microscopy (SEM), mechanical and physical properties (such as density, viscosity and electrical conductivity) of the composite fibres were evaluated. Moreover, a cell culture test was performed in order to determine their cytotoxicity for wound dressing application. Results: The effect of starch ratio in the solution on the properties and morphological structure of the fibers produced was presented. With lower starch concentration values, the fibers have greater ultimate tensile strength characteristic (mostly 4 and 5 wt%). According to SEM results, it can be figured out that the nanofibers fabricated have good spinnability and morphology. The mean diameter of the fibers is about 150 nm. According to results of cell culture study, the finding can be determined that the increase of starch in the fiber also increases the cell viability. Conclusions: Composite nanofibers of starch/ PCL have been prepared using a coaxial needle electrospinning technique. PCL was successfully encapsulated within starch. Fiber formation was observed for different ratio of starch. With several test, analysis and measurement performed, some important parameters such as quality and effectuality of each fiber obtained for wound dressing applications were discussed in detail.Publication Metadata only Novel electrospun polycaprolactone/graphene oxide/Fe3O4 nanocomposites for biomedical applications(ELSEVIER SCIENCE BV, 2018) OKTAR, FAİK NÜZHET; Aydogdu, Mehmet Onur; Ekren, Nazmi; Suleymanoglu, Mediha; Erdem-Kuruca, Serap; Lin, Chi-Chang; Bulbul, Ertugrul; Erdol, Meltem Nur; Oktar, Faik Nuzhet; Terzi, Umit Kemalettin; Kilic, Osman; Gunduz, OguzhanIn this study, one of the most promising methods of tailoring a composite scaffold material in nano sized diameters, electrospinning method were used to produce Polycaprolactone (PCL)/Graphene Oxide (GO)/Iron(II, III) Oxide (Fe3O4) nanocomposite fibers as biocompatible scaffolds for biomedical applications. Products were analyzed by scanning electron microscopy (SEM) for morphological analysis of the electrospun nanocomposites and Fourier Transform Infrared Spectroscopy (FTIR) was used to determine functional groups of the PCL, GO, and Fe3O4 materials in the electrospun nanocomposites. For physical properties, viscosity, density, permittivity, dielectric loss and liquid and solid state alternating current conductivity, measurements were done for each nanocomposite fibers. Effects of concentration percentage of GO on permittivity, dielectric loss and AC conductivity have been analyzed by using measured and calculated data. Trend lines have been drawn for permittivity, dielectric loss and conductivity via concentration percentage of GO. The relation between ac conductivity and frequency have been studied for each concentration percentage of GO and interpretations have been done by using the obtained results.Publication Metadata only Production and characterization of electrospun fish sarcoplasmic protein based nanofibers(ELSEVIER SCI LTD, 2018) KAZAN, DİLEK; Sahin, Yesim M.; Su, Sena; Ozbek, Burak; Yucel, Sevil; Pinar, Orkun; Kazan, Dilek; Oktar, Faik N.; Ekren, Nazmi; Gunduz, OguzhanIn this study, poly (e-caprolactone) (PCL) and fish sarcoplasmic protein (FSP) (Mw < 200 kDa) composite nanofibers were fabricated by electrospinning technique. Solution properties such as density, viscosity, conductivity and surface tension were studied as a function of FSP content in the solution. The morphology, molecular interaction, degradation as well as thermal and tensile properties of PCL/FSP nanofibers were investigated. The results show that smooth and beadless PCL/FSP nanofibers with the diameters ranging from 120 +/- 29 nm to 139 +/- 41 nm were obtained. The average diameters decreased and the diameter distributions narrowed with the addition of optimum FSP amount. The characteristic picks of FSP and PCL were identified in the composite nanofibers by structural analyses. PCL/FSP nanofibers exhibited high degradation ability in comparison to electrospun pure PCL nancifibers. Moreover, the PCL/FSP nanofibers exhibit good mechanical properties (tensile strength of 5.55 MPa) with the additional FSP content. (C) 2017 Elsevier Ltd. All rights reserved.Publication Metadata only Nanofibrous wound dressing material by electrospinning method(TAYLOR & FRANCIS AS, 2019) İNAN, AHMET TALAT; Yeniay, Eda; Ocal, Leyla; Altun, Esra; Giray, Betul; Oktar, Faik Nuzhet; Inan, Ahmet Talat; Ekren, Nazmi; Kilic, Osman; Gunduz, OguzhanWound dressings are very useful materials for accelerating the wound healing process. In this study, nanofibrous wound dressings were produced from blending solution of Poly-lactic acid(PLA)/Chitosan(C)/Starch(S)/Zinc oxide(Z) by electrospinning method. Morphology, chemical interaction, mechanical, water uptake and weight loss tests were performed on each samples. Moreover, the biocompatibility of primary dermal fibroblast (ATCC, PCS-201-012) on prepared wound dressings was investigated with MTT assays in vitro, and the samples were found suitable for cell viability and proliferation. These results suggest that produced nanofibrous wound dressings can be promising candidate for wound dressing applications. [GRAPHICS] .Publication Metadata only Magnetic Core Shell Structures: From 0D to 1D Assembling(BENTHAM SCIENCE PUBL LTD, 2015) İNAN, AHMET TALAT; Ficai, Denisa; Ficai, Anton; Dinu, Elena; Oprea, Ovidiu; Sonmez, Maria; Keler, Memduh Kagan; Sahin, Yesim Muge; Ekren, Nazmi; Inan, Ahmet Talat; Daglilar, Sibel; Gunduz, OguzhanMaterial research and development studies are focused on different techniques of bringing out nanomaterials with desired characteristics and properties. From the point of view of materials development, nowadays scientists are strongly focused on obtaining materials with predefined characteristics and properties. The morphology control seems to be a determinant factor and increasing attention is devoted to this aspect. At this moment it is possible to engineer the material's features by using different methods and materials combination for both medical and industrial applications. In the applications of chemistry and synthesis, biology, mechanics, optics solar cells and microelectronics tailoring the adjustable parameters of stoichiometry, chemical structure, shape and segregation are evaluated and opens new fields. Because of the magnetic features of nanoparticles and durable particle size, less than 100 nm, this study is aiming to describe their uses in practical applications. That's why the whole hydrodynamic magnetic core shell topic will be reviewed on this paper. Additionally, the properties acting in general sight in solid-state physics are utilized for material selection and for defining issue connecting the core, shell structure and their producing properties. Here, in the study of core/shell nanoparticle various physical and chemical synthesis routes and the effect of electrospun method are briefly discussed. Starting from a real void of the scientific literature, the existent data related to the 1D magnetic electrospun materials are reviewed. The perspectives in the medical, environmental or energetic sector is great and bring some real advantages related to the 0D core@shell structures because both mechanical and biological properties are dependent on the morphology of the materials.Publication Metadata only Production of the novel fibrous structure of poly(epsilon-caprolactone)/tri-calcium phosphate/hexagonal boron nitride composites for bone tissue engineering(AUSTRALIAN CERAMIC SOCIETY, 2018) OKTAR, FAİK NÜZHET; Ozbek, Burak; Erdogan, Barkin; Ekren, Nazmi; Oktar, Faik Nuzhet; Akyol, Sibel; Ben-Nissan, Besim; Sasmazel, Hilal Turkoglu; Kalkandelen, Cevriye; Mergen, Ayhan; Kuruca, Serap Erdem; Ozen, Gunes; Gunduz, OguzhanNanofibrous composites of the poly(epsilon-caprolactone) (PCL), tricalcium phosphate (TCP), and hexagonal boron nitride (h-BN) with different compositions were manufactured by using an economical and non-complicated method called electrospinning. Produced fibrous structures showed no bead formation and had a clean surface. Characterization of the composites showed that particles were successfully mixed with polymer phase. High cell activity of SaOS-2 cells on the composites was observed with SEM images. In addition, fibrous scaffolds are biocompatible with human bone tissue and are highly degradable.