Şaşmazel, Hilal Türkoğlu
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S.,Hilal Turkoglu
Sasmazel, Hilal Tuerkoglu
Sasmazel, Hilal Turkoglu
H. T. Şaşmazel
Turkoglu Sasmazel H.
Sasmazel,H.T.
Şaşmazel,H.T.
Hilal Türkoğlu, Şaşmazel
H., Sasmazel
Şasmazel H.
S., Hilal Turkoglu
Ş.,Hilal Türkoğlu
Ş., Hilal Türkoğlu
Turkoğlu Şaşmazel H.
Hilal Turkoglu, Sasmazel
H.T.Sasmazel
H.T.Şaşmazel
Sasmazel H.
Sasmazel, H. T.
Türkoglu, H
Turkoglu, Hilal
Sasmazel, H. Turkoglu
Sasmazel, Hilal T.
H. T. Sasmazel
Şaşmazel, Hilal Türkoğlu
H.,Şaşmazel
Şaşmazel H.
Sasmazel, H. Tuerkodlu
Türkoǧlu Şaşmazel,H.
Şaşmazel, Hilal
Sasmazel, Hilal Tuerkoglu
Sasmazel, Hilal Turkoglu
H. T. Şaşmazel
Turkoglu Sasmazel H.
Sasmazel,H.T.
Şaşmazel,H.T.
Hilal Türkoğlu, Şaşmazel
H., Sasmazel
Şasmazel H.
S., Hilal Turkoglu
Ş.,Hilal Türkoğlu
Ş., Hilal Türkoğlu
Turkoğlu Şaşmazel H.
Hilal Turkoglu, Sasmazel
H.T.Sasmazel
H.T.Şaşmazel
Sasmazel H.
Sasmazel, H. T.
Türkoglu, H
Turkoglu, Hilal
Sasmazel, H. Turkoglu
Sasmazel, Hilal T.
H. T. Sasmazel
Şaşmazel, Hilal Türkoğlu
H.,Şaşmazel
Şaşmazel H.
Sasmazel, H. Tuerkodlu
Türkoǧlu Şaşmazel,H.
Şaşmazel, Hilal
Job Title
Profesor Doktor
Email Address
hilal.sasmazel@atilim.edu.tr
ORCID ID
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Turkish CoHE Profile ID
Google Scholar ID
WoS Researcher ID
Scholarly Output
48
Articles
33
Citation Count
750
Supervised Theses
9
48 results
Scholarly Output Search Results
Now showing 1 - 10 of 48
Article Citation Count: 15Macroporous silicone biomaterials with modified surface chemistry: Production and characterization(Sage Publications Ltd, 2012) Şaşmazel, Hilal Türkoğlu; Odabas, Sedat; Sasmazel, Hilal T.; Piskin, Erhan; Metallurgical and Materials EngineeringPorous and bioactive silicone biomaterials were developed for soft and cartilage tissue repair. A protocol, using compression molding, salt extraction, and supercritical carbon dioxide treatments, was used to obtain disk-shaped materials with specific pore sizes and morphologies by changing the process conditions. Highly open/interconnected macroporous silicone matrices, with an average pore size of 250-300 mu m and porosities in the range of 60%-70%, were obtained by the extracting the NaCl particles. Subsequent treatment with supercritical carbon dioxide slightly decreased the average pore size but increased the porosity to 80%. The supercritical carbon dioxide treatment effectively removed the entrapped salt crystals from the silicone matrix that improved interconnectivity. The compression modulus decreased, while the compression strength was increased using this technique. The surfaces and pores of the silicone materials were modified by silanization to provide primary amine groups for cell attachment, proliferation, migration, and three-dimensional growth of model L929 fibroblast cells.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: 1Physico-chemical characterization and in vitro biological study of manganese doped β-tricalcium phosphate-based ceramics for bone regeneration applications(Springer, 2023) Şaşmazel, Hilal Türkoğlu; Daglilar, Sibel; Kalkandelen, Cevriye; Balescu, Liliana-Marinela; Sasmazel, Hilal Turkoglu; Pasuk, Iuliana; Gunduz, Oguzhan; Metallurgical and Materials EngineeringThis 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 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.Master Thesis Poli(vinil alkol) grafen nanokompozitlerin geliştirilmesi(2017) Şaşmazel, Hilal Türkoğlu; Şaşmazel, Hilal Türkoğlu; Metallurgical and Materials EngineeringÇalışmanın amacı, polivinil alkol (PVA) ve grafenin formlarından indirgenmiş grafen oksit (rGO) ve kimyasal buharla biriktirilmiş (CVD) tek tabaka grafenin elektroeğirilmesiyle olası uygulamalarda (paketleme, elektriksel, termal ve doku mühendisliği) kullanılmak üzere yeni nanokompozitlerin elde edilmesidir. Bu amaç doğrultusunda iki farklı yöntem kullanılmıştır. Bunlardan ilki satın alınan PVA ve farklı yüzdelerdeki (ağırlıkça % 0.5 ve 1) rGO karışımının elektroeğirilmesiyken, diğeri PVA'nın CVD tek tabaka grafene elektroeğirilmesidir. Elde edilen nanokompozitlerin UV ışını ile çapraz bağlanmasının ardından, her iki tip malzemenin karakterizasyon özelliklerinin belirlenmesi; kalınlık, iletkenlik ve yüzey temas açısı (CA) ölçümleri, taramalı elektron mikroskobu (SEM), termogravimetrik (TGA) ve su, mekanik ve degredasyon (bozunma) testleri ve PBS şişme ve büzüşme davranış tayinleri ile yapılmıştır. Bunun yanı sıra rGO/PVA nanokompozitlerinin kimyasal kompozisyonları Fourier Dönüşümlü Kızılötesi Spektrofotometre (FTIR), kristal yapıdaki değişim X-ışını Kırınım (XRD) ile incelenmiş ek olarak su buharı geçirgenlik analizleri (WVTR) yapılmış; PVA elektroğrilmiş CVD tek tabaka grafen nanokompozitleri için ayrıca optik mikroskop ve Raman analizleri yapılmıştır. Bu analizler sonucunda, en yüksek fiber çapı ~340 nm ile elektroeğirilmiş %0.5 rGO+PVA nanokompozitleri için ölçülürken, en yüksek elektrik iletkenlik değeri elektroeğirilmiş % 1.0 rGO+PVA nanokompozitleri için ~11 μS.cm-1 olarak bulunmuştur. Bu analizlere ek olarak, hazırlanan nanokompozitlerin hücre-materyal etkileşimleri MG-63 hücre hattı kullanılarak gerçekleştirilmiştir. Tüm bu analizlerin sonucunda % 1.0 rGO+PVA tipi nanokompozitin olası uygulamalarda (paketleme, elektriksel, termal ve doku mühendisliği) kullanmak üzere oldukça uygun ve yararlı bir malzeme olduğu anlaşılmıştır.Article Citation Count: 9Manufacturing of Zinc Oxide Nanoparticle (ZnO NP)-Loaded Polyvinyl Alcohol (PVA) Nanostructured Mats Using Ginger Extract for Tissue Engineering Applications(Mdpi, 2022) Şaşmazel, Hilal Türkoğlu; Ilhan, Elif; Kalkandelen, Cevriye; Celen, Emrah; Guncu, Mehmet Mucahit; Sasmazel, Hilal Turkoglu; Constantinescu, Gabriel; Metallurgical and Materials EngineeringIn this research, as an alternative to chemical and physical methods, environmentally and cost-effective antimicrobial zinc oxide nanoparticles (ZnO NP) were produced by the green synthesis method. The current study focuses on the production of ZnO NP starting from adequate precursor and Zingiber officinale aqueous root extracts (ginger). The produced ZnO NP was loaded into electrospun nanofibers at different concentrations for various tissue engineering applications such as wound dressings. The produced ZnO NPs and ZnO NP-loaded nanofibers were examined by Scanning Electron Microscopy (SEM) for morphological assessments and Fourier-transform infrared spectrum (FT-IR) for chemical assessments. The disc diffusion method was used to test the antimicrobial activity of ZnO NP and ZnO NP-loaded nanofibers against three representatives strains, Escherichia coli (Gram-negative bacteria), Staphylococcus aureus (Gram-positive bacteria), and Candida albicans (fungi) microorganisms. The strength and stretching of the produced fibers were assessed using tensile tests. Since water absorption and weight loss behaviors are very important in tissue engineering applications, swelling and degradation analyses were applied to the produced nanofibers. Finally, the MTT test was applied to analyze biocompatibility. According to the findings, ZnO NP-loaded nanofibers were successfully synthesized using a green precipitation approach and can be employed in tissue engineering applications such as wound dressing.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] .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.Master Thesis Elektroeğirme prosesi boyunca sıcaklık ve nem parametrelerinin kitosan fiberler üzerine etkisi(2020) Şaşmazel, Hilal Türkoğlu; Şaşmazel, Hilal Türkoğlu; İşgör, Sultan Belgin; Metallurgical and Materials EngineeringBu çalışmada, doğal biyobozunur polisakkarit, kitosan (CS), kullanılarak nanofiberler elde edilmiştir. Elektroeğirme işleminin sıcaklık ve nem parametrelerinin kitoson fiberler üzerine etkisi optimize edilmiş parametrelerle araştırılmıştır. Bu parametrelerden iğne ve toplayıcı arasındaki mesafe 7 cm'dir. Ek olarak, akış hızı 2 μl/dk iken, uygulanan voltaj ise 16,5 kV'dir. Kullanılan polimer çözeltisi, kitosan polimerinin trifloroasetik asit (TFA) içerisinde 50 – 55°C'de sıcak plaka üzerinde manyetik karıştırıcı ile homojen çözelti elde edilene kadar karıştırılması ile elde edilmiştir. Kitosan fiberlerinin karakteristik özellikleri SEM, ATR-FTIR ve DSC ile tayin edilmiştir. Kitosan fiberlerinin morfolojik özellikleri Taramalı Elektron Mikroskopisi (SEM) ile, kimyasal yapı analizi ise Zayıflatılmış Toplam Yansıma - Fourier Dönüşümlü Kızılötesi Spektrometresi (ATR-FTIR) ile incelenmiştir. Farklı sıcaklık ve nem parametreleri için erime entalpisi ve sıcaklık değişimleri Diferansiyel Taramalı Kalorimetre (DSC) ile belirlenmiştir. Ortalama fiber çapı, gözenek boyutu dağılımı ve yüzde gözeneklilik değerleri, SEM analizinden alınan fotoğraflarla ImageJ programı (Versiyon, 1.52a) kullanılarak tayin edilmiştir. Ortalama fiber çapı (260 ± 2.20 – 442 ± 2.72 nm), gözenek boyutu dağılımı (0.039 ± 0.004 – 0.063 ± 0.007 μm) ve yüzde gözeneklilik ise (% 49 – 60) aralığında bulunmuştur. SEM analizi sonuçlarına göre sıcaklık artışı ile; ortalama fiber çapı azalmış, gözenek boyutu dağılımı ve yüzde gözeneklilik ise artmıştır. Buna karşılık nem artışı ile ise; ortalama fiber çapı, gözenek boyutu dağılımı ve yüzde gözeneklilik artmıştır. ATR-FTIR sonuçları ile, kitosanın kimyasal yapısının çeşitli ortam parametreleri için aynı bileşime sahip olduğu görülmüştür. Kitosan fiberlerinin termal özellikleri DSC ile araştırılmış, sonuçlar kitosan fiberi üretimindeki sıcaklık ve nem değişikliğinin erime entalpisi ve sıcaklığında değişime yol açtığını göstermiştir.
