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Article Citation - WoS: 45Citation - Scopus: 46Novel Hybrid Scaffolds for the Cultivation of Osteoblast Cells(Elsevier, 2011) Sasmazel, Hilal TurkogluIn this study, natural biodegradable polysaccharide, chitosan, and synthetic biodegradable polymer, poly(epsilon-caprolactone) (PCL) were used to prepare 3D, hybrid polymeric tissue scaffolds (PCL/chitosan blend and PCL/chitosan/PCL layer by layer scaffolds) by using the electrospinning technique. The hybrid scaffolds were developed through HA addition to accelerate osteoblast cell growth. Characteristic examinations of the scaffolds were performed by micrometer, SEM, contact angle measurement system, ATR-FTIR, tensile machine and swelling experiments. The thickness of all electrospun scaffolds was determined in the range of 0.010 +/- 0.001-0.012 +/- 0.002 mm. In order to optimize electrospinning processes, suitable bead-free and uniform scaffolds were selected by using SEM images. Blending of PCL with chitosan resulted in better hydrophilicity for the PCL/chitosan scaffolds. The characteristic peaks of PCL and chitosan in the blend and layer by layer nanofibers were observed. The PCL/chitosan/PCL layer by layer structure had higher elastic modulus and tensile strength values than both individual PCL and chitosan structures. The layer by layer scaffolds exhibited the PBS absorption values of 184.2; 197.2% which were higher than those of PCL scaffolds but lower than those of PCL/chitosan blend scaffolds. SaOs-2 osteosarcoma cell culture studies showed that the highest ALP activities belonged to novel PCL/chitosan/PCL layer by layer scaffolds meaning better cell differentiation on the surfaces. (C) 2011 Elsevier B.V. All rights reserved.Article Citation - WoS: 18Citation - Scopus: 19Effects of Nozzle Type Atmospheric Dry Air Plasma on L929 Fibroblast Cells Hybrid Poly (ε-caprolactone)/Chitosan (ε-Caprolactone) Scaffolds Interactions(Soc Bioscience Bioengineering Japan, 2016) Ozkan, Ozan; Sasmazel, Hilal TurkogluIn the study presented here, in order to improve the surface functionality and topography of poly (epsilon-caprolactone) (PCL)/chitosan/PCL hybrid tissue scaffolds fabricated layer by layer with electrospinning technique, an atmospheric pressure nozzle type plasma surface modification was utilized. The optimization of the plasma process parameters was carried out by monitoring the changes in surface hydrophilicity by using contact angle measurements. SEM, AFM and XPS analyses were utilized to observe the changes in topographical and chemical properties of the modified surfaces. The results showed that applied plasma modification altered the nanotopography and the functionality of the surfaces of the scaffolds. The modification applied for 9 min from a distance of 17 cm was found to provide the possible contact angle value (75.163 +/- 0.083) closest to the target value which is the value of tissue culture polystyrene (TCPS) petri dishes (similar to 49.7 degrees), compared to the unmodified samples (84.46 +/- 3.86). In vitro cell culture was carried out by L929 mouse fibroblast cell line in order to examine the effects of plasma surface modification on cell material interactions. Standard MIT assay showed improved cell viability on/within modified scaffolds confirmed with the observations of the cell attachment and the morphology by means of SEM, fluorescence and confocal imaging. The experiments performed in the study proved the enhanced biocompatibility of the nozzle type dry air plasma modified scaffolds. (C) 2016, The Society for Biotechnology, Japan. All rights reserved.Article Citation - WoS: 11Development of Antibacterial Composite Electrospun Chitosan-Coated Polypropylene Materials(Amer Scientific Publishers, 2018) Gozutok, Melike; Basar, Ahmet Ozan; Sasmazel, Hilal TurkogluIn this study, a natural antibacterial substance chitosan was coated with/without potassium sorbate (KS) (0.8% (w/w) of KS, 8% (w/v) chitosan) onto the polypropylene (PP) film by using electrospinning technique to obtain novel antibacterial composite materials for various applications such as wound dressing, tissue engineering, drug delivery and food packaging. Atmospheric pressure plasma surface treatment was applied onto polypropylene films in order to increase its wettability thus enhancing the adhesion capacity of the films and the optimum CA value was determined as 42.75 +/- 0.80 degrees. Scanning Electron Microscope (SEM) and X-ray Photoelectron Spectroscopy (XPS) analyses were realized to observe the morphological changes and chemical properties of the samples, respectively. Contact angle measurements, tensile testing, oxygen and water vapor transmission rate analyses were performed to obtain wettability values, mechanical properties and WVTRs, respectively. The WVTR was increased by plasma treatment and addition of KS (from 14.264 +/- 0.214% to 21.020 +/- 0.659%). The desired antibacterial performance of the samples was assessed with Staphylococcus aureus and Escherichia coli by inhibition ratio calculation and disc diffusion assay. The highest inhibition ratios were found as 64% for S. aureus and 92% for E. coli for plasma-treated CS-KS-PP films.Correction Influence of Water/O2 Plasma Treatment on Cellular Responses of Pcl and Pet Surfaces (vol 21, Pg 123, 2011)(Ios Press, 2011) Sasmazel, Hilal Turkoglu; Aday, Sezin; Manolache, Sorin; Gumusderelioglu, Menemse[No Abstract Available]Article Citation - WoS: 22Citation - Scopus: 24Mechanical and Biological Properties of Al2o3< and Tio2 Co-Doped Zirconia Ceramics(Elsevier Sci Ltd, 2017) Agac, Ozlem; Gozutok, Melike; Sasmazel, Hilal Turkoglu; Ozturk, Abdullah; Park, JongeeVarious amounts (ranging from 0 to 2 wt%) of TiO2 and Al2O3 were mono and co-doped to tetragonal zirconia ceramic containing 3 mol% yttria (3Y-TZP) by mechanical ball milling. Powders were compacted by uniaxial pressing at a pressure of 23 MPa. The compacts were pressureless sintered at 1450 degrees C for 2 h. Density, hardness, fracture toughness, and cell attachment of the co-doped 3Y-TZP ceramics were measured with respect to dopant addition to determine the effects of the kind and amount of dopants on the properties. The results show that density decreased gradually as the amount of dopant was increased. The mechanical properties showed the maximum value when 0.5 wt% TiO2 and 1.0 wt% Al2O3 were co-doped to 3Y-TZP. Crystalline phase formation and microstructural morphology were investigated by XRD and SEM analyses to explain the variations in the properties. Co-doping of TiO2 and Al2O3 to 3Y-TZP did not have an influence on the phases present, but decreased the grain size. The co-doping also affected the cell attachment and the growth on the surface of the zirconia ceramics.Article Citation - WoS: 3Citation - Scopus: 3Physical and Biological Characteristics of Electrospun Poly (vinyl Alcohol) and Reduced Graphene Oxide Nanofibrous Structure(Taylor & Francis Ltd, 2024) Sasmazel, Hilal Turkoglu; Alazzawi, Marwa; Gozutok, Melike; Sadhu, VeeraThe fabrication of graphene-based nanocomposites has been a topic of increasing interest due to graphene's exceptional physical properties and the ability to enhance the properties of various polymeric materials. Evaluating the biocompatibility of these nanocomposites is crucial to ensure their safe and effective use in biomedical applications. This study characterized and assessed the biocompatibility of previously fabricated electrospun polyvinyl alcohol (PVA)/reduced graphene oxide rGO fibrous structures by conducting a comprehensive assessment of their physical and biological characteristics. Contact angle measurements revealed that adding rGO to electrospun PVA fibers enhanced the surface wettability, improving the fibrous structure's PBS absorption capacity and degradation behavior. Including the rGO content resulted in a higher water vapor transmission rate, reaching similar to 48 g/m2day for PVA + 0.5 wt.% rGO and similar to 45 g/m2day for PVA + 1.0 wt.% rGO, compared to similar to 40 g/m2day for electrospun PVA fibers. Cell culture studies, including MTT assay, alkaline phosphatase (ALP) activity analysis, alizarin red staining, fluorescence microscopy, and SEM analyses, demonstrated that electrospun PVA + 1.0 wt.% rGO nanocomposites exhibited superior cell viability, proliferation, and growth compared to other samples, due to the improved physical properties of the PVA + 1.0 wt.% rGO fibrous structure.Article Citation - WoS: 5Citation - Scopus: 5Physico-Chemical Characterization and in Vitro Biological Study of Manganese Doped Β-Tricalcium Phosphate-Based Ceramics for Bone Regeneration Applications(Springer, 2023) Arpak, Mehmet Can; Daglilar, Sibel; Kalkandelen, Cevriye; Balescu, Liliana-Marinela; Sasmazel, Hilal Turkoglu; Pasuk, Iuliana; Gunduz, OguzhanThis work evaluates the effects of manganese (Mn) doping on the morpho-structural features, mechanical performance, and in vitro biological response of beta-tricalcium phosphate (beta-TCP) derived bioceramics for bone tissue engineering applications. Five different Mn doping levels (i.e., 0.01%, 0.05%, 0.1%, 0.5%, and 1 wt.%) were investigated, with the beta-TCP-based bioceramics being sintered at four temperatures (i.e., 1000, 1100, 1200, and 1300 degrees C). A densification improvement was induced when using Mn in excess of 0.05 wt.%; the densification remained stationary in the sintering temperature range of 1200 - 1300 degrees C. The structural analyses evidenced that all samples sintered at 1000 and 1100 degrees C were composed of beta-TCP as major phase and hydroxyapatite (HA) as a minor constituent (similar to 4-6 wt.%). At the higher temperatures (1200 and 1300 degrees C), the formation of alpha-TCP was signalled at the expense of both beta-TCP and HA. The Mn doping was evidenced by lattice parameters changes. The evolution of the phase weights is linked to a complex inter-play between the capacity of the compounds to incorporate Mn and the thermal decomposition kinetics. The Mn doping induced a reduction in the mechanical performance (in terms of compressive strength, Vickers hardness and elastic modulus) of the beta-TCP-based ceramics. The metabolic activity and viability of osteoblastic cells (MC3T3-E1) for the ceramics were studied in both powder and compacted pellet form. Ceramics with Mn doping levels lower than 0.1 wt.% yielded a more favorable microenvironment for the osteoblast cells with respect to the undoped beta-TCP. No cytotoxic effects were recorded up to 21 days. The Mn-doped beta-TCPs showed a significant increase (p < 0.01) in alkaline phosphatase activity with respect to pure beta-TCP.Article Citation - WoS: 21Citation - Scopus: 18Dbd Atmospheric Plasma-Modified, Electrospun, Layer-By Polymeric Scaffolds for L929 Fibroblast Cell Cultivation(Taylor & Francis Ltd, 2016) Surucu, Seda; Sasmazel, Hilal TurkogluThis paper reported a study related to atmospheric pressure dielectric barrier discharge (DBD) Ar+O-2 and Ar+N-2 plasma modifications to alter surface properties of 3D PCL/Chitosan/PCL layer-by-layer hybrid scaffolds and to improve mouse fibroblast (L929 ATCC CCL-1) cell attachment, proliferation, and growth. The scaffolds were fabricated using electrospinning technique and each layer was electrospun sequentially on top of the other. The surface modifications were performed with an atmospheric pressure DBD plasma under different gas flow rates (50, 60, 70, 80, 90, and 100sccm) and for different modification times (0.5-7min), and then the chemical and topographical characterizations of the modified samples were done by contact angle (CA) measurements, scanning electron microscopy (SEM), atomic force microscopy, and X-ray photoelectron spectroscopy. The samples modified with Ar+O-2 plasma for 1min under 70cm(3)/min O-2 flow rate (71.077 degrees +/- 3.578) showed a 18.83% decrease compare to unmodified samples' CA value (84.463 degrees +/- 3.864). Comparing with unmodified samples, the average fiber diameter values for plasma-modified samples by Ar+O-2 (1min 70sccm) and Ar+N-2 (40s 70sccm) increased 40.756 and 54.295%, respectively. Additionally, the average inter-fiber pore size values exhibited decrease of 37.699 and 48.463% for the same Ar+O-2 and Ar+N-2 plasma-modified samples, respectively, compare to unmodified samples. Biocompatibility performance was determined with MTT assay, fluorescence, Giemsa, and confocal imaging as well as SEM. The results showed that Ar+O-2-based plasma modification increased the hydrophilicity and oxygen functionality of the surface, thus affecting the cell viability and proliferation on/within scaffolds.Article Citation - WoS: 10Citation - Scopus: 11Functionalization of Nonwoven Pet Fabrics by Water/O2< Plasma for Biomolecule Mediated Cell Cultivation(Wiley-v C H verlag Gmbh, 2010) Sasmazel, Hilal Turkoglu; Manolache, Sorin; Gumusderelioglu, MenemseThe main target of this study was to obtain COOH functionalities on the surface of 3D, nonwoven polyethylene terephthalate fabrics (NWPFs) by using low pressure water/O-2 plasma assisted treatment. The plasma treatments were performed in a cylindrical, capacitively coupled RF-plasma-reactor and then following steps were performed: in situ (oxalyl chloride vapors) gas/solid reaction to convert -OH functionalities into COCl groups; and hydrolysis under open laboratory conditions using air moisture for final-COOH functionalities. COOH and OH functionalities on the surfaces were detected quantitatively by fluorescent labeling techniques. The COOH-functionalized samples were biologically activated with insulin or heparin molecules by using spacer polyoxyethylene bis-amine (PEO). Successful immobilization was checked qualitatively using electron spectroscopy for chemical analysis (ESCA). The average amount of immobilized insulin and heparin onto NWPF surfaces were determined as 146.09 and 4.81 nmol.cm(-2), respectively. Our results showed that water/O-2 plasma assisted treatment worked very well for functionalization and biofunctionalization of 3D NWPF disks comparing with wet-chemistry methods. Cell culture experiments indicated that functionalization of NWPF disks and/or nanotopographies on the disk surfaces were effective on adhesion and proliferation of L929 mouse fibroblasts.Article Citation - WoS: 57Citation - Scopus: 60Atmospheric Plasma Surface Modifications of Electrospun Pcl/Chitosan Hybrid Scaffolds by Nozzle Type Plasma Jets for Usage of Cell Cultivation(Elsevier Science Bv, 2016) Surucu, Seda; Masur, Kai; Sasmazel, Hilal Turkoglu; Von Woedtke, Thomas; Weltmann, Klaus DieterThis paper reports Ar gas, Ar + O-2, Ar + O-2 + N-2 gas mixtures and dry air plasma modifications by atmospheric pressure argon driven kINPen and air driven Diener (PlasmaBeam) plasma jets to alter surface properties of three dimensional (3D), electrospun PCL/Chitosan/PCL layer by layer hybrid scaffolds to improve human fibroblast (MRC5) cell attachment and growth. The characterizations of the samples were done by contact angle (CA) measurements, scanning electron microscopy (SEM), X-Ray Photoelectron spectroscopy (XPS) analysis. The results showed that the plasma modification carried out under dry air and Ar + O-2 + N-2 gas mixtures were altered effectively the nanotopography and the functionality of the material surfaces. It was found that the samples treated with Ar + O-2 + N-2 gas mixtures for 1 min and dry air for 9 min have better hydrophilicity 78.9 degrees + 1.0 and 75.6 degrees + 0.1, respectively compared to the untreated samples (126.5 degrees). Biocompatibility performance of the scaffolds was determined with alamarBlue (aB) assay and MTT assay methods, Giemsa staining, fluorescence microscope, confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM) analyses. The results showed that plasma treated samples increased the hydrophilicity and oxygen functionality and topography of the surfaces significantly, thus affecting the cell viability and proliferation on/within scaffolds. (C) 2016 Elsevier B.V. All rights reserved.
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