Browsing by Author "Sasmazel, Hilal Turkoglu"
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Article Citation Count: 19Antibacterial Performance of PCL-Chitosan Core-Shell Scaffolds(Amer Scientific Publishers, 2018) Özkan, Ozan; Sasmazel, Hilal Turkoglu; Şaşmazel, Hilal Türkoğlu; Metallurgical and Materials EngineeringIn this study, antibacterial performance of the coaxially electrospun Poly-epsilon-caprolactone (PCL)-chitosan core-shell scaffolds developed, optimized and identified physically and chemically in our previous study, were evaluated for the suitability in wound healing applications. The aim of utilizing a core-shell fibrous scaffold with PCL as core and chitosan as shell was to combine natural biocompatibility, biodegradability and antibacterial properties of chitosan with mechanical properties and resistance to enzymatic degradation of PCL. The scaffolds were prepared with the optimized parameters, obtained from our previous study. Thickness and contact angle measurements as well as Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) analyses confirmed repeated fabrication of PCL-chitosan core-shell scaffolds. In this study, assays specific to wound dressing materials, such as water vapor transmission rate (WVTR), in vitro degradability and antibacterial tests were carried out. WVTR value of PCL-chitosan core-shell scaffolds was higher (2315 +/- 3.4 g/m(2).day) compared to single PCL scaffolds (1654 +/- 3.2 g/m(2).day) due to the higher inter-fiber pore size. Additionally, in vitro degradability assays showed that the susceptibility of chitosan to enzymatic degradation can be significantly improved by hybridization with more resistant PCL while still keeping the scaffold to be considered as biodegradable. Finally, inhibition ratio and inhibition zone measurements showed that the PCL-chitosan core-shell polymeric scaffolds had significant antibacterial performance (52.860 +/- 2.298% and 49.333 +/- 0.719% inhibition ratios; 13.975 +/- 0.124 mm and 12.117 +/- 0.133 mm clear inhibition zones, against E. coli and S. aureus, respectively), close to the native chitosan. Therefore, the developed scaffolds can be considered as suitable candidates for biodegradable wound dressing applications.Article Citation Count: 51Atmospheric plasma surface modifications of electrospun PCL/chitosan/PCL hybrid scaffolds by nozzle type plasma jets for usage of cell cultivation(Elsevier Science Bv, 2016) Şaşmazel, Hilal Türkoğlu; Masur, Kai; Sasmazel, Hilal Turkoglu; Von Woedtke, Thomas; Weltmann, Klaus Dieter; Metallurgical and Materials EngineeringThis 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.Review Citation Count: 36Atmospheric Pressure Plasma Surface Treatment of Polymers and Influence on Cell Cultivation(Mdpi, 2021) Şaşmazel, Hilal Türkoğlu; Alazzawi, Marwa; Alsahib, Nabeel Kadim Abid; Metallurgical and Materials EngineeringAtmospheric plasma treatment is an effective and economical surface treatment technique. The main advantage of this technique is that the bulk properties of the material remain unchanged while the surface properties and biocompatibility are enhanced. Polymers are used in many biomedical applications; such as implants, because of their variable bulk properties. On the other hand, their surface properties are inadequate which demands certain surface treatments including atmospheric pressure plasma treatment. In biomedical applications, surface treatment is important to promote good cell adhesion, proliferation, and growth. This article aim is to give an overview of different atmospheric pressure plasma treatments of polymer surface, and their influence on cell-material interaction with different cell lines.Article Citation Count: 63Coaxial and emulsion electrospinning of extracted hyaluronic acid and keratin based nanofibers for wound healing applications(Pergamon-elsevier Science Ltd, 2021) Şaşmazel, Hilal Türkoğlu; Bedir, Tuba; Kalkandelen, Cevriye; Basar, Ahmet Ozan; Sasmazel, Hilal Turkoglu; Ustundag, Cem Bulent; Gunduz, Oguzhan; Metallurgical and Materials EngineeringNovel composites based on poly(epsilon-caprolactone)/polyethylene oxide loaded with hyaluronic acid(HA) and keratin(KR) were produced separately using emulsion and coaxial electrospinning methods. HA and KR were extracted from animal sources, characterized and loaded into coaxial fiber structures as bioactive agents, separately and together. Morphological, chemical, thermal, and mechanical characteristics of the fibers were investigated. According to the SEM results, diameters of smooth and beadless fibers fabricated via emulsion method were at nanoscale (sub-micron) while fibers of coaxial method were at micro scale. Benefitted electrospinning techniques demonstrated that hydrophobic and hydrophilic polymers can be advantageously combined. Core polymer specific FT-IR bands were not visible, their presence was proven with DSC analysis which confirms core-shell morphology of the fibers. In vitro studies exhibited spun mats did not have any cytotoxic effects and the HA and KR incorporated into the fiber structure synergistically increased cell viability and cell proliferation. This study demonstrated that the electrospun fibers containing HA and KR fabricated by both emulsion and coaxial methods can be efficient for wound healing applications.Article Citation Count: 8Core/Shell Glycine-Polyvinyl Alcohol/Polycaprolactone Nanofibrous Membrane Intended for Guided Bone Regeneration: Development and Characterization(Mdpi, 2021) Şaşmazel, Hilal Türkoğlu; Alsahib, Nabeel Kadim Abid; Sasmazel, Hilal Turkoglu; Metallurgical and Materials EngineeringGlycine (Gly), which is the simplest amino acid, induces the inflammation response and enhances bone mass density, and particularly its beta polymorph has superior mechanical and piezoelectric properties. Therefore, electrospinning of Gly with any polymer, including polyvinyl alcohol (PVA), has a great potential in biomedical applications, such as guided bone regeneration (GBR) application. However, their application is limited due to a fast degradation rate and undesirable mechanical and physical properties. Therefore, encapsulation of Gly and PVA fiber within a poly(epsilon-caprolactone) (PCL) shell provides a slower degradation rate and improves the mechanical, chemical, and physical properties. A membrane intended for GBR application is a barrier membrane used to guide alveolar bone regeneration by preventing fast-proliferating cells from growing into the bone defect site. In the present work, a core/shell nanofibrous membrane, composed of PCL as shell and PVA:Gly as core, was developed utilizing the coaxial electrospinning technique and characterized morphologically, mechanically, physically, chemically, and thermally. Moreover, the characterization results of the core/shell membrane were compared to monolithic electrospun PCL, PVA, and PVA:Gly fibrous membranes. The results showed that the core-shell membrane appears to be a good candidate for GBR application with a nano-scale fiber of 412 +/- 82 nm and microscale pore size of 6.803 +/- 0.035 mu m. Moreover, the wettability of 47.4 +/- 2.2 degrees contact angle (C.A) and mechanical properties of 135 +/- 3.05 MPa average modulus of elasticity, 4.57 +/- 0.04 MPa average ultimate tensile stress (UTS), and 39.43% +/- 0.58% average elongation at break are desirable and suitable for GBR application. Furthermore, the X-ray diffraction (XRD) and transmission electron microscopy (TEM) results exhibited the formation of beta-Gly.Article Citation Count: 19DBD atmospheric plasma-modified, electrospun, layer-by-layer polymeric scaffolds for L929 fibroblast cell cultivation(Taylor & Francis Ltd, 2016) Şaşmazel, Hilal Türkoğlu; Sasmazel, Hilal Turkoglu; Metallurgical and Materials EngineeringThis 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 Count: 9Development of Antibacterial Composite Electrospun Chitosan-Coated Polypropylene Materials(Amer Scientific Publishers, 2018) Şaşmazel, Hilal Türkoğlu; Basar, Ahmet Ozan; Sasmazel, Hilal Turkoglu; Metallurgical and Materials EngineeringIn 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.Article Citation Count: 78Development of core-shell coaxially electrospun composite PCL/chitosan scaffolds(Elsevier, 2016) Şaşmazel, Hilal Türkoğlu; Sasmazel, Hilal Turkoglu; Metallurgical and Materials EngineeringThis study was related to combining of synthetic Poly (epsilon-caprolactone) (PCL) and natural chitosan polymers to develop three dimensional (3D) PCL/chitosan core-shell scaffolds for tissue engineering applications. The scaffolds were fabricated with coaxial electrospinning technique and the characterizations of the samples were done by thickness and contact angle (CA) measurements, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-Ray Photoelectron Spectroscopy (XPS) analyses, mechanical and PBS absorption and shrinkage tests. The average inter-fiber diameter values were calculated for PCL (0.717 +/- 0.001 mu m), chitosan (0.660 +/- 0.007 mu m) and PCL/chitosan core-shell scaffolds (0.412 +/- 0.003 mu m), also the average inter-fiber pore size values exhibited decreases of 66.91% and 61.90% for the PCL and chitosan scaffolds respectively, compared to PCL/chitosan core-shell ones. XPS analysis of the PCL/chitosan core-shell structures exhibited the characteristic peaks of PCL and chitosan polymers. The cell culture studies (MTT assay, Confocal Laser Scanning Microscope (CLSM) and SEM analyses) carried out with L929 ATCC CCL-1 mouse fibroblast cell line proved that the biocompatibility performance of the scaffolds. The obtained results showed that the created micro/nano fibrous structure of the PCL/chitosan core-shell scaffolds in this study increased the cell viability and proliferation on/within scaffolds. (C) 2016 Elsevier B.V. All rights reserved.Article Citation Count: 0Development of Electrospun WE43 Magnesium Alloy-Like Compound(Amer Scientific Publishers, 2020) Özkan, Ozan; Sasmazel, Hilal Turkoglu; Şaşmazel, Hilal Türkoğlu; Metallurgical and Materials EngineeringMetallic structures are conventionally fabricated with high temperature/deformation processes resulting the smallest possible microscopic structures in the order of several hundreds of micrometer. Therefore, to obtain structures with fibers smaller than 100 Am, those are unsuitable. In this study, electrospinning, a fiber fabrication technique commonly used for polymers, was adopted to fabricate a WE43 magnesium alloy-like fibrous structure. The aim is to adopt metallic WE43 alloy to regenerative medicine using tissue engineering approach by mimicking its composition inside of a fibrous structure. The solution required for electrospinning was obtained with water soluble nitrates of elements in WE43 alloy, and PVP or PVA were added to obtain a spinnable viscosity which was pyrolised away during heat treatment. Electrospinning parameters were optimized with naked-eye observations and SEM as 1.5 g salts and 5 wt.% PVA containing solution prepared at 90 degrees C and electrospun under 30 kV from a distance of 12-15 cm with a feeding rate of 5 mu l/min. Then the samples were subjected to a multi-step heat treatment under argon to remove the polymer and calcinate the nitrates into oxides which was designed based on thermal analyses and reaction kinetics calculations as 6 h at 230 degrees C, 8.5 h at 390 degrees C, 5 h at 465 degrees C, 80 h at 500 degrees C and 10 h at 505 degrees C, consecutively. The characterizations conducted in terms of structure, composition and crystallinity with XRD, XPS, EDX and SEM showed that it is possible to obtain MgaYbNdcZrdOx), (empirical) fibers with the same composition as WE43 in sub-millimeter sizes using this approach.Article Citation Count: 15Development of Poly(vinyl alcohol) (PVA)/Reduced Graphene Oxide (rGO) Electrospun Mats(Amer Scientific Publishers, 2019) Şaşmazel, Hilal Türkoğlu; Sadhu, Veera; Sasmazel, Hilal Turkoglu; Metallurgical and Materials EngineeringIn this study, electrospun reduced graphene oxide (rGO) and poly(vinyl alcohol) (PVA) nanocomposites were developed with the concentration of rGO as 0.5 and 1.0 wt% by dispersing rGO in the PVA solution without using any co-solvent which may cause toxic effect for possible applications like packaging and tissue engineering. Water solubility of PVA was eliminated by UV-radiation crosslinking method. SEM analysis proved that continuous and bead-free nanofibers were obtained by electrospinning process and all electrospun mats had similar fiber characteristics with homogeneous fiber morphology. The average fiber diameter (nm), inter-fiber pore size (mu m) and the porosity (%) were increased with rGO incorporation. Additionally, enhanced tensile properties was achieved by rGO addition as the highest tensile strength was obtained as similar to 5 MPa for electrospun PVA+ 1.0 wt% rGO nanocomposites. ATR-FTIR analyses showed that there was a relatively strong interfacial interaction between rGO and PVA. Moreover, the thermal stability of obtained nanocomposites was enhanced by rGO addition without changing the crystal structure of PVA proved by XRD analyses. Also, improved electrical conductivity of the nanocomposites was obtained by rGO content as the highest conductivity (similar to 11 mu S.cm(-1)) was measured for electrospun PVA+ 1.0 wt% rGO.Article Citation Count: 5Dielectric barrier discharge and jet type plasma surface modifications of hybrid polymeric poly (ε-caprolactone)/chitosan scaffolds(Sage Publications Ltd, 2018) Özkan, Ozan; Sasmazel, Hilal Turkoglu; Şaşmazel, Hilal Türkoğlu; Metallurgical and Materials EngineeringIn this study, dry air plasma jet and dielectric barrier discharge Ar+O-2 or Ar+N-2 plasma modifications and their effects on wettability, topography, functionality and biological efficiency of the hybrid polymeric poly (epsilon-caprolactone)/chitosan scaffolds were reported. The samples treated with Ar+O-2 dielectric barrier discharge plasma (80 sccm O-2 flow rate, 3-min treatment) or with dry air plasma jet (15-cm nozzle-sample distance, 13-min treatment) had the closest wettability (49.11 +/- 1.83 and 53.60 +/- 0.95, respectively) to the commercial tissue culture polystyrene used for cell cultivation. Scanning electron microscopy images and X-ray photoelectron spectrometry analysis showed increase in topographical roughness and OH/NH2 functionality, respectively. Increased fluid uptake capacity for the scaffolds treated with Ar+O-2 dielectric barrier discharge plasma (73.60%+/- 1.78) and dry air plasma jet (72.48%+/- 0.75) were also noted. Finally, initial cell attachment as well as seven-day cell viability, growth and proliferation performances were found to be significantly better for both plasma treated scaffolds than for untreated scaffolds.Article Citation Count: 5A drug-eluting nanofibrous hyaluronic acid-keratin mat for diabetic wound dressing(Springernature, 2022) Şaşmazel, Hilal Türkoğlu; Bedir, Tuba; Kalkandelen, Cevriye; Sasmazel, Hilal Turkoglu; Basar, Ahmet Ozan; Chen, Jing; Gunduz, Oguzhan; Metallurgical and Materials EngineeringDiabetes mellitus is a chronic metabolic disease associated with long-term multisystem complications, among which are non-healing diabetic foot ulcers (DFUs). Electrospinning is a sophisticated technique for the preparation of polymeric nanofibers impregnated with drugs for wound healing, burns, and diabetic ulcers. This study describes the fabrication and characterization of a novel drug-eluting dressing made of core-shell structured hyaluronic acid (HA)-keratin (KR)-polyethylene oxide (PEO) and polycaprolactone (PCL) nanofibers to treat diabetic wounds. The core-shell nanofibers produced by the emulsion electrospinning technique provide loading of metformin hydrochloride (MH), HA, and KR in the core of nanofibers, which in return improves the sustained long term release of the drug and prolongs the bioactivity. Morphological and chemical properties of the fibers were examined by SEM, FTIR, and XRD studies. It was observed that the fibers which contain HA and KR showed thin fiber structure, greater swelling capacity, fast degradation and increased cumulative drug release amount than neat emulsion fibers due to the hydrophilic nature of HA and KR. MH showed a sustained release from all fiber samples over 20 days and followed the first-order and Higuchi model kinetics and Fickian diffusion mechanism according to kinetic analysis results. In vitro cell culture studies showed that the developed mats exhibited enhanced biocompatibility performance with HA and KR incorporation. The results show that HA and KR-based emulsion electrospun fiber mats are potentially useful new nanofiber-based biomaterials in their use as drug carriers to treat diabetic wounds.Editorial Citation Count: 0Editorial: Biofabricated materials for tissue engineering(Frontiers Media Sa, 2024) Şaşmazel, Hilal Türkoğlu; Gunduz, Oguzhan; Ramalingam, Murugan; Ulag, Songul; Metallurgical and Materials Engineering[No Abstract Available]Article Citation Count: 18Effects of nozzle type atmospheric dry air plasma on L929 fibroblast cells hybrid poly (ε-caprolactone)/chitosan/poly (ε-caprolactone) scaffolds interactions(Soc Bioscience Bioengineering Japan, 2016) Özkan, Ozan; Sasmazel, Hilal Turkoglu; Şaşmazel, Hilal Türkoğlu; Metallurgical and Materials EngineeringIn 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 Count: 53Electrospun Oxygen Scavenging Films of Poly(3-hydroxybutyrate) Containing Palladium Nanoparticles for Active Packaging Applications(Mdpi, 2018) Şaşmazel, Hilal Türkoğlu; Gozutok, Melike; Sasmazel, Hilal Turkoglu; Torres-Giner, Sergio; Lagaron, Jose M.; Metallurgical and Materials EngineeringThis paper reports on the development and characterization of oxygen scavenging films made of poly(3-hydroxybutyrate) (PHB) containing palladium nanoparticles (PdNPs) prepared by electrospinning followed by annealing treatment at 160 degrees C. The PdNPs were modified with the intention to optimize their dispersion and distribution in PHB by means of two different surfactants permitted for food contact applications, i.e., hexadecyltrimethylammonium bromide (CTAB) and tetraethyl orthosilicate (TEOS). Analysis of the morphology and characterization of the chemical, thermal, mechanical, and water and limonene vapor barrier properties and the oxygen scavenging capacity of the various PHB materials were carried out. From the results, it was seen that a better dispersion and distribution was obtained using CTAB as the dispersing aid. As a result, the PHB/PdNP nanocomposites containing CTAB provided also the best oxygen scavenging performance. These films offer a significant potential as new active coating or interlayer systems for application in the design of novel active food packaging structures.Article Citation Count: 19Encapsulation of β-Carotene by Emulsion Electrospraying Using Deep Eutectic Solvents(Mdpi, 2020) Şaşmazel, Hilal Türkoğlu; Prieto, Cristina; Durand, Erwann; Villeneuve, Pierre; Sasmazel, Hilal Turkoglu; Lagaron, Jose; Metallurgical and Materials EngineeringThe encapsulation beta-carotene in whey protein concentrate (WPC) capsules through the emulsion electrospraying technique was studied, using deep eutectic solvents (DES) as solvents. These novel solvents are characterized by negligible volatility, a liquid state far below 0 degrees C, a broad range of polarity, high solubilization power strength for a wide range of compounds, especially poorly water-soluble compounds, high extraction ability, and high stabilization ability for some natural products. Four DES formulations were used, based on mixtures of choline chloride with water, propanediol, glucose, glycerol, or butanediol. beta-Carotene was successfully encapsulated in a solubilized form within WPC capsules; as a DES formulation with choline chloride and butanediol, the formulation produced capsules with the highest carotenoid loading capacity. SEM micrographs demonstrated that round and smooth capsules with sizes around 2 mu m were obtained. ATR-FTIR results showed the presence of DES in the WPC capsules, which indirectly anticipated the presence of beta-carotene in the WPC capsules. Stability against photo-oxidation studies confirmed the expected presence of the bioactive and revealed that solubilized beta-carotene loaded WPC capsules presented excellent photo-oxidation stability compared with free beta-carotene. The capsules developed here clearly show the significant potential of the combination of DES and electrospraying for the encapsulation and stabilization of highly insoluble bioactive compounds.Article Citation Count: 9Functionalization of Nonwoven Pet Fabrics by Water/O2 Plasma for Biomolecule Mediated Cell Cultivation(Wiley-v C H verlag Gmbh, 2010) Şaşmazel, Hilal Türkoğlu; Manolache, Sorin; Gumusderelioglu, Menemse; Metallurgical and Materials EngineeringThe 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 Count: 7Hybrid polymeric scaffolds prepared by micro and macro approaches(Taylor & Francis As, 2017) Özkan, Ozan; Sasmazel, Hilal Turkoglu; Şaşmazel, Hilal Türkoğlu; Metallurgical and Materials EngineeringPolymeric scaffolds with complex porous structures were fabricated with two different polymers by combining three fabrication methods in three steps, in which, nonwoven poly(e-caprolactone) microfibers were obtained with electrospinning and immersed in solvent cast chitosan solution poured in Petri dish to fabricate hybrid polymers, and finally the combined structure was freeze-dried with two different predrying techniques to obtain macropores in the structure. The resulting hybrid polymeric mats were found to have both microfibers and macroporosity due to the electrospinning as well as freeze-drying processes, which resemble the natural extracellular matrix. The optimized scaffolds that predried in the incubator at 40 degrees C for 5 h and then freeze-dried for 24 h exhibited contact angle value of 68.93 +/- 2.18 degrees with 3.252 +/- 0.783 MPa Young's modulus and 0.260 +/- 0.002 MPa yield strength as well as 1.35-fold cell yield in MRC5 fibroblast cell culture, compared to the commercial tissue culture polystyrene. [GRAPHICS] .Conference Object Citation Count: 0Impact of Nanotopography and/or Functional Groups on Periodontal Ligament Cell Growth(Springer, 2010) Şaşmazel, Hilal Türkoğlu; Manolache, S.; GumusderlIoglu, M.; Metallurgical and Materials EngineeringThe main purpose of this contribution was to obtain COOH functionalities and/or nanotopographic changes on the surface of 3D, non-woven polyester fabric (NWPF) discs (12.5 mm in diameter) by using low pressure water/O-2 plasma assisted treatments. The prepared discs were characterized by various methods after the plasma treatment. Periodontal ligament (PDL) fibroblasts were used in cell culture studies. The cell culture results showed that plasma treated 3D NWPF discs are favorable for PDL cell spreading, growth and viability due to the presence of functional groups and/or the nanotopography of their surfaces.Article Citation Count: 1In vitro evaluation of tooth-colored yttria stabilized zirconia ceramics(Taylor & Francis Ltd, 2021) Park, Jongee; Basar, Ahmet Ozan; Şaşmazel, Hilal Türkoğlu; Park, Jongee; Ozturk, Abdullah; Metallurgical and Materials EngineeringEffects of MoCl3 and NiCl2, originally incorporated as coloring agent, on the cellular response of 3 mol% yttria stabilized zirconia (3Y-TZP) ceramics was investigated. MoCl3 and NiCl2-MoCl3 incorporated, tooth-colored 3Y-TZP ceramics were produced through cold isostatic pressing at 100 MPa followed by pressureless sintering at 1450 degrees C for 2 h. Aging was performed on the sintered ceramics using distilled water in a reactor at 134 degrees C at 2.3 bar pressure for 2 h. The phases developed during different stages of processing were identified by X-ray diffraction (XRD) analysis. In vitro cell culture studies were carried out using L929 fibroblast cell line. The cell viability and proliferation studies revealed that none of the specimens showed cytotoxicity with respect to coloring. Confocal laser scanning microscope (CLSM) analyses suggested that all of the specimens exhibited good in vitro cytocompatibility. Enhancement in cell attachment, adhesion, and proliferation was observed in all specimens via scanning electron microscope (SEM) analysis. Although the coloring process did not improve the proliferation performance of the aged specimens, the incorporation of transition metals enhanced the in vitro performance of 3Y-TZP ceramics.