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Öğe Assessing short-term effects of magnetite ferrite nanoparticles on Daphnia magna(Springer Heidelberg, 2020) Gokce, Didem; Koytepe, Suleyman; Ozcan, ImrenMagnetic nanoparticles (MNPs) are used in a wide range of sectors ranging from electronics to biomedicine, as well as in eutrophicated lake restoration due to their high P, N, and heavy metal adsorption capacity. This study assessed the effects of MNPs on mortality and morphometric changes of D. magna. According to the SEM, the synthesised MNPs were found to have spherical nanoparticles, be uniformly distributed, and have a homolithic size distribution of 50-110 nm. The EDX spectra confirmed the elemental structure and purities of these MNPs. A total of 396 neonates were used for short-term bioassays (96 h) through the MNPs in the laboratory (16:8 photoperiod). Experiments were applied in triplicate for each concentration of CuFe2O4, CoFe2O4, and NiFe2O4 MNPs and their respective control groups. Mortality and morphological measurements of each individual were recorded every 24 h. In the probit analysis, the 96-h LC50 (p < 0.05) for CuFe2O4, CoFe2O4, and NiFe2O4 MNPs was calculated to be 1.455 mg L-1, 39.834 mg L-1, and 21.730 mg L-1, respectively. CuFe2O4 MNPs were found to be more toxic than the other two MNPs. The concentrations of CuFe2O4, CoFe2O4, and NiFe2O4 MNPs drastically affected life span and morphologic growth of D. magna as a result of a short time exposure. The results of this study are useful for assessing what risks they pose to freshwater ecosystems.Öğe Chemistry and engineering of brush type polymers: Perspective towards tissue engineering(Elsevier, 2022) Acari, Idil Karaca; Sel, Evren; Ozcan, Imren; Ates, Burhan; Koytepe, Sueleyman; Thakur, Vijay KumarIn tissue engineering, it is imperative to control the behaviour of cells/stem cells, such as adhesion, proliferation, propagation, motility, and differentiation for tissue regeneration. Surfaces that allow cells to behave in this way are critical as support materials in tissue engineering. Among these surfaces, brush-type polymers have an important potential for tissue engineering and biomedical applications. Brush structure and length, end groups, bonding densities, hydrophilicity, surface energy, structural flexibility, thermal stability, surface chemical reactivity, rheological and tribological properties, electron and energy transfer ability, cell binding and absorption abilities for various biological molecules of brush-type polymers were increased its importance in tissue engineering applications. In addition, thanks to these functional properties and adjustable surface properties, brush type polymers are used in different high-tech applications such as electronics, sensors, anti-fouling, catalysis, purification and energy etc. This review comprehensively highlights the use of brush-type polymers in tissue engineering applications. Considering the superior properties of brush-type polymer structures, it is believed that in the future, it will be an effective tool in structure designs containing many different biomolecules (enzymes, proteins, etc.) in the field of tissue engineering.Öğe The Cytotoxicity, DNA Fragmentation, and Decreasing Velocity Induced By Chromium(III) Oxide on Rainbow Trout Spermatozoa(Springernature, 2023) Ozgur, Mustafa Erkan; Ulu, Ahmet; Gurses, Canbolat; Ozcan, Imren; Noma, Samir Abbas Ali; Koytepe, Suleyman; Ates, BurhanThe present study aimed to determine the cytotoxicity of chromium(III) oxide micro particles (Cr2O3-Ps) in rainbow trout (Oncorhynchus mykiss) spermatozoa. Firstly, Cr2O3-Ps were synthesized and structurally characterized the surface, morphological for particle size and thermal properties. In addition, its structural and elemental purity was determined using energy-dispersive X-ray (EDX) spectrum and elemental maps. Structural purity, thermal properties, and stability of Cr2O3 -Ps were also examined in detail by performing thermal analysis techniques. The cytotoxicity of Cr2O3-Ps was measured by the observation of velocities, antioxidant activities, and DNA damages in rainbow trout spermatozoa after exposure during 3 h in vitro incubation. The straight line velocity (VSL), the curvilinear velocity (VCL), and the angular path velocity (VAP) of spermatozoa decreased after exposure to Cr2O3-Ps. While the superoxide dismutase (SOD) and the catalase (CAT) decreased, the lipid peroxidation increased in a dose-dependent manner. However, the total glutathione (tGSH) was not affected in this period. DNA damages were also determined in spermatozoa using Comet assay. According to DNA in tail (%) data, DNA damages have been detected with gradually increasing concentrations of Cr2O3-Ps. Furthermore, all of class types which are categorized as the intensity of DNA fragmentation has been observed between 50 and 500 mu g/L concentrations of Cr2O3-Ps exposed to rainbow trout spermatozoa. At the end of this study, we determined that the effective concentrations (EC50) were 76.67 mu g/L for VSL and 87.77 mu g/L for VCL. Finally, these results about Cr2O3-Ps may say to be major risk concentrations over 70 mu g/L for fish reproduction in aquatic environments.Öğe Design of epoxy-functionalized Fe3O4@MCM-41 core-shell nanoparticles for enzyme immobilization(Elsevier, 2018) Ulu, Ahmet; Ozcan, Imren; Koytepe, Suleyman; Ates, BurhanThe scope of our research was to prepare the organosilane-modified Fe3O4@MCM-41 core-shell magnetic nano particles, used for L-ASNase immobilization and explored screening of immobilization conditions such as pH, temperature, thermal stability, kinetic parameters, reusability and storage stability. In this content, Fe3O4 core shell magnetic nanoparticles were prepared via co-precipitation method and coated with MCM-41. Then, Fe3O4@MCM-41 magnetic nanoparticles were functionalized by (3-glycidyloxypropyl) trimethoxysilane (GPTMS) as an organosilane compound. Subsequently, L-ASNase was covalently immobilized on epoxyfunctionalized Fe3O4@MCM-41 magnetic nanoparticles. The immobilized L-ASNase had greater activity at high pH and temperature values. It also maintained >92% of the initial activity after incubation at 55 degrees C for 3 h. Regarding kinetic values, immobilized L-ASNase showed a higher Vmax and lower Km compared to native L-ASNase. In addition, it displayed excellent reusability for 12 successive cycles. After 30 days of storage at 4 degrees C and 25 degrees C, immobilized L-ASNase retained 54% and 26% of its initial activities while native L-ASNase lost about 68% and 84% of its initial activity, respectively. As a result, the immobilization of L-ASNase onto magnetic nanoparticles may provide an advantage in terms of removal of L-ASNase from reaction media. (C) 2018 Elsevier B.V. All rights reserved.Öğe Development of gallic acid sensors based on polyimide-modified platinum electrode(Taylor & Francis Inc, 2019) Pasahan, Aziz; Ayhan, Nurcan; Ozcan, Imren; Duran, Serap Titretir; Koytepe, SuleymanA series aromatic polyimide (PI) membranes in the form of permselective films was synthesised from different dianhydrides with two diamine monomers for gallic acid (GA) measurement. The obtained PI films were examined by Spectroscopic techniques, Scanning Electron Microscopy (SEM) and thermal analysis techniques and then used to fabricate the selective films on the modified electrode. Because of their excellent film properties, as the permselective polymeric membranes were used for determination of GA in the presence of various interferences and real sample. The PI-1-modified Pt electrode showed a very high R-value (0.9935) and reproducibility for GA determination, as well as high selectivity. [GRAPHICS]Öğe Differential Pulse Voltammetric (DPV) Determination of the Local Anesthetic Bupivacaine using Polyimide Membrane-Based Electrodes(Taylor & Francis Inc, 2020) Gungor, Oznur; Ozcan, Imren; Erdogan, Mehmet Ali; Ates, Burhan; Koytepe, SuleymanAromatic selective polyimide (PI) membrane based voltammetric electrodes were prepared for bupivacaine measurements. Polyimide membranes were synthesized from 4,4 '-diaminobenzanilide (DABA) and different aromatic dianhydrides (pyromellitic dianhydride (PMDA), benzophenone-3,3 ',4,4 '-tetracarboxylic dianhydride (BPDA), 4,4 '-oxydiphthalic anhydride (ODPA)) through two-step polycondenzation reactions. The structural properties of the obtained benzanilide based PIs were characterized by various analytical techniques. For the preparation of voltammetric electrodes, these polyimide films were coated with polyimide solution by drop-casting on the surface of a platinum working electrode. Due to the excellent film properties and suitable porosity, the prepared benzanilide based polyimide films were used as the membrane for selective determination of bupivacaine in the presence of interferents that included lactose, glucose and sucrose. For this reason, the selectivity of the modified electrode to bupivacaine obtained from the prepared PI film toward the potential interferences was investigated by differential pulse voltammetry (DPV). The results of voltammetric study showed that polyimide films responded to only bupivacaine at a potential of approximately +0.92 V. The polyimide membrane modified electrode showed a rapid response time, a high R-value of 0.9941, high reproducibility and good selectivity for bupivacaine. The limit of detection (LOD) and the limit of quantitation (LOQ) were determined to be 16.82 mu M and 50.46 mu M, respectively. Thus, benzanilide based polyimides may be successfully used as selective membranes for preparation of bupivacaine sensors. This structure may be a precursor for the preparation of simultaneous or needle-shaped sensors in the future.Öğe Effects of nanoparticles on Daphnia magna population dynamics(Taylor & Francis Ltd, 2018) Gokce, Didem; Koytepe, Suleyman; Ozcan, ImrenSpherical TiO2 nanoparticles (npTiO(2)) were prepared by controlled hydrolysis of tetraethoxy orthotitanate under a nitrogen atmosphere. ZnO nanoparticles (npZnO) were prepared using hydrothermal methods. The crystal structure, chemical, thermal and morphological properties of npZnO and npTiO(2) were characterised using Fourier Transform Infrared Spectrometer, enery-dispersive X-ray spectroscopy, X-ray diffraction, and scanning electron microscope techniques. The short- and long-term experiments were started with neonates taken from the same culture and laboratory condition. In the acute experiments, npTiO(2), npZnO, and cocktail concentrations were applied. 96h-LC50 values were 1.8, 0.7, and 0.1mgL(-1), respectively (p<.05). For the chronic experiments, different npTiO(2) concentrations were performed. 21d-LC50 value was 1.0mgL(-1) (p<.05). Morphometry became progressively worse in concentrations of more than 1mgL(-1) npTiO(2). Neonate and young individuals were more sensitive to death because of their low tolerance. This result was affected by population progeny and growth rates (p<.05). While control and 0.5mgL(-1) npTiO(2) groups were determined as growing population, 1.5 and 2mgL(-1) npTiO(2) groups had decreased population size as R-0 values. Consequently, the relationships between nanoparticle accumulation within Daphnia magna and its population structure and body morphometry for each concentration were important indicators. Its tolerance level to nanoparticles under laboratory conditions reflected its replacement and behaviour in the ecosystem.Öğe The effects of urea content on the structural, thermal and morphological properties of MgO nanopowders(Elsevier Sci Ltd, 2018) Ercan, Ismail; Kaygili, Omer; Ates, Tankut; Gunduz, Bayram; Bulut, Niyazi; Koytepe, Suleyman; Ozcan, ImrenIn the present study, we have looked into the effects of the amount of the combustion fuel of urea on the morphological, thermal and morphological properties of MgO structure. To this goal, three Magnesium Oxide (MgO) samples were synthesized by the combustion method and the as-mentioned properties were characterized by the experimental analysis techniques of X-Ray Diffraction (XRD), Differential Thermal Analysis (DTA), Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM). The functional groups in the samples were also determined using Fourier Transform Infrared (FTIR) spectrometry. The crystallinity percent values for each sample were found to be about in the range of 94-96%. The crystallite sizes of the samples were computed to be in the ranges of 26-37 nm and 23-32 nm for Scherrer and Williamson-Hall methods, respectively. The increasing quantity of urea caused a gradual growth in the lattice parameter of Magnesium Oxide structure. The thermal properties and morphology were affected by the urea content.Öğe The effects of Zn and Yb co-dopants on the electronic, radiation shielding, structural, thermal and spectroscopic properties of hydroxyapatite(Elsevier, 2024) Ayhan, Yasemin Merve; Ates, Tankut; Seckin, Turgay; Ozcan, Imren; Bulut, Niyazi; Kurucay, Ali; Kaygili, OmerThis work presents a comprehensive investigation of the electronic properties of hydroxyapatite (HA) doped with zinc (Zn) and ytterbium (Yb). Four different compositions, namely 0.33Zn-0.33Yb-HA, 0.33Zn-0.66Yb-HA, 0.66Zn-0.33Yb-HA, and 0.66Zn-0.66Yb-HA, were studied using Density of States (DOS) and band structure calculations. The computed band gap values for each composition were determined to be 4.3097 eV, 4.1324 eV, 4.2527 eV, and 4.2088 eV, respectively. The observed decrease in the band gap energy from 0.33Zn-0.33Yb-HA to 0.66Zn-0.66Yb-HA signifies a significant impact of the dopant composition on the electronic properties of the material. Furthermore, the inclusion of ytterbium in the HA matrix resulted in the formation of a distinct band and peak in the density of states. This indicates the emergence of specific energy levels associated with Yb, suggesting a distinct influence on the electronic structure of the material. These findings provide valuable insights into the tunability of the electronic properties of HA through controlled doping with Zn and Yb. Such knowledge is crucial for tailoring materials with desired electronic characteristics, thus holding promise for various applications in electronic devices and biocompatible coatings. The as-modeled structures were synthesized via a wet chemical route. Fourier transform infrared (FTIR), Raman, and X-ray diffraction (XRD) analyses verified the formation of the HA structure for each sample. Differential thermal analysis (DTA) results showed that all the as-prepared samples were thermally stable. The negligible mass losses were detected for all the samples in the thermogravimetric analysis (TGA) measurements. The addition of both co-dopants affected crystal structure related parameters and decreased the crystallinity and cell viability.Öğe Electrochemical determination of ceftriaxone using polyurethane-modified electrode containing caffeic acid and chitosan(Taylor & Francis Inc, 2022) Hassine, Chedia Ben Ali; Gungor, Oznur; Burc, Muammer; Ozcan, Imren; Koytepe, Suleyman; Duran, Serap TitretirThe aim of this work was to develop an electrochemical sensor based on caffeic acid and chitosan-containing polyurethane (CAC-PU) films modified platinum electrode for ceftriaxone (CFX) determination. For this aim, firstly the CAC-PU structures were synthesized from three different diisocyanates and these structures were characterized with spectroscopic, thermal and surface analysis techniques. Then, these CAC-PU structures were coated on bare Pt electrode surface for the preparation of CFX selective sensors. Throughout this study several analytical parameters, such as film thickness, electrolyte type, pH effect, and scan rate were investigated by using differential pulse voltammetry (DPV) method. Under the optimized conditions, the voltammetric test results showed best analytical performances for CFX detection with a linear range from 0.1 to 1.5 mM. Limit of detection (LOD) and correlation coefficient (R-2) were obtained 52 mu M and 0.9991 using CAC-PU modified electrode, respectively. Stability of the modified electrode was found to be 96.78% by using reproducibility experiments (n = 10). Applicable of the presented sensor was tested in two synthetic urine samples and recoveries values were obtained 98.7% and 110%, respectively. The prepared modified electrode exhibits high repeatability, fast response, and high sensitivity, which makes it suitable for the detection of CFX in urine samples.Öğe The in vitro toxicity analysis of titanium dioxide (TiO2) nanoparticles on kinematics and biochemical quality of rainbow trout sperm cells(Elsevier Science Bv, 2018) Ozgur, Mustafa Erkan; Balcioglu, Sevgi; Ulu, Ahmet; Ozcan, Imren; Okumus, Fatih; Koytepe, Suleyman; Ates, BurhanIn recent years, titanium dioxide (TiO2) nanoparticles (NPs) as metal oxide nanoparticles are widely used in industry, agriculture, personal care products, cosmetics, sun protection and toothpaste, electronics, foodstuffs and food packaging. This use of nano-TiO2 has been associated with environmental toxicity concerns. Therefore, the aim of this study was to evaluate the in vitro effect of different doses of TiO2 NPs (similar to 30-40 nm) (0.01, 0.1, 0.5, 1, 10 and 50 mg/L) at 4oC for 3 h on the sperm cell kinematics as velocities of Rainbow trout (Oncorhynchus mykiss, Walbaum, 1792) sperm cells. Furthermore, oxidative stress markers (total glutathione (TGSH) and superoxide dismutase (SOD) were assessed in sperm cells after exposure to TiO2 NPs. According to the obtained results, there were statistically significant (P < 0.05) decreasing in the velocities of sperm cells after 10 mg/L TiO2 NPs and an increase the activity of SOD (P < 0.05) and TGSH levels were determined.Öğe Interaction of nickel ferrite nanoparticles with nucleic acids(Elsevier, 2022) Topkaya, Seda Nur; Acari, Idil Karaca; Kaya, Huseyin Oguzhan; Ozcan, Imren; Koytepe, Suleyman; Cetin, Arif E.In this article, we introduced an electrochemical biosensor employing graphite electrodes (GE) decorated with Nickel ferrite (NiFe2O4) nanoparticles for nucleic acid detection. NiFe2O4 nanoparticles in a narrow size distribution were synthesized with co-precipitation technique. Their chemical and crystallographic properties were characterized with FTIR and X-ray spectroscopies. Nanoparticle size distribution and hydrodynamic diameter were determined with particle size analyzer. Elemental content and purity of nanoparticles were analyzed with EDX analysis. Our analyses showed a diameter of similar to 10 nm for NiFe2O4 nanoparticles. Electrochemical properties of NiFe2O4 nanoparticles were examined with different analysis methods. Conductivity properties of NiFe2O4 nanoparticles were investigated with Cyclic Voltammetry (CV), which confirmed that nanoparticles on GE surface have a high surface area and conductivity. More importantly, in this article, the interactions between NiFe2O4 nanoparticles and double stranded DNA (dsDNA), single stranded DNA (ssDNA), and RNA were for the first time examined using Differential Pulse Voltammetry (DPV), CV, and Electrochemical Impedance Spectroscopy (EIS). Oxidation peak currents of NiFe2O4 nanoparticles and guanine bases of dsDNA, ssDNA, and RNA showed that NiFe2O4 nanoparticles effectively interacts with nucleic acids via an electrostatic mode.Öğe Investigation of toxic effects of amorphous SiO2 nanoparticles on motility and oxidative stress markers in rainbow trout sperm cells(Springer Heidelberg, 2019) Ozgur, Mustafa Erkan; Ulu, Ahmet; Ozcan, Imren; Balcioglu, Sevgi; Ates, Burhan; Koytepe, SuleymanIn this study, we investigated the effects of SiO2 nanoparticles (SiO2-NPs) (1, 10, 25, 50, and 100mg/L) for 24h in vitro on the motility parameters and oxidative stress markers such as total glutathione (TGSH), catalase (CAT), and malondialdehyde (MDA) of rainbow trout, Oncorhynchus mykiss sperm cells. Therefore, SiO2-NPs were synthesized with sol-gel reaction from tetraethoxy orthosilicate (TEOS). The prepared nanoparticle structures were characterized for chemical structure, morphology and thermal behavior employing Fourier transform infrared spectroscopy, X-ray spectroscopy, scanning electron micrograph, and thermal analysis (DTA/TGA/DSC) techniques. After exposure, there was statistically significant (p<0.05) decreases in velocities of sperm cells. CAT activity significantly (p<0.05) decreased by 9.6% in sperm cell treated with 100mg/L. In addition, MDA level significantly increased by 70.4% and 77.5% in sperm cell treated with 50 and 100mg/L SiO2-NPs, respectively (p<0.05). These results showed that SiO2-NPs may have toxic effect on rainbow trout sperm cells in 50mg/L and more.Öğe Melatonin protects sperm cells of Capoeta trutta from toxicity of titanium dioxide nanoparticles(Springer Heidelberg, 2020) Ozgur, Mustafa Erkan; Ulu, Ahmet; Noma, Samir Abbas Ali; Ozcan, Imren; Balcioglu, Sevgi; Ates, Burhan; Koytepe, SuleymanIn this study, it was aimed to determine the protective effects of melatonin (0.01, 0.1, and 1 mM) against 10 mg/L titanium dioxide nanoparticles (TiO2-NPs) on kinematic and oxidative indices in the sperm cells of Capoeta trutta. Therefore, TiO2 nanoparticles were synthesized primarily within the scope of the study. The synthesized nanoparticles were characterized by structurally different techniques. Then, melatonin and TiO2 were applied to Capoeta trutta sperm cells by in vitro. According to our data, all doses of melatonin showed protective effects on all velocities of sperm cells such as the straight line velocity (VSL), the curvilinear velocity (VCL), and the angular path velocity (VAP) against TiO2-NPs, while 0.1 and 1 mM doses of melatonin improved the VSL value. Although TiO2-NPs increased total glutathione (tGSH), malondialdehyde (MDA) lipid peroxidation, and superoxide dismutase (SOD) compared to the control group, there were positive treatment effects for all doses of melatonin on antioxidant capacity of sperm cells. At the end of this research, it is suggested that over 0.1 mM dose of melatonin improves the velocity of sperm cells and it plays a protective role against the toxic effects of TiO2-NPs.Öğe Photocrosslinkable gelatin/collagen based bioinspired polyurethane-acrylate bone adhesives with biocompatibility and biodegradability(Elsevier, 2021) Balcioglu, Sevgi; Gurses, Canbolat; Ozcan, Imren; Yildiz, Azibe; Koytepe, Suleyman; Parlakpinar, Hakan; Vardi, NigarHard or soft tissue adhesives have been presented as a promising candidate to replace traditional wound closure methods. However, there are mechanical strength problems in biological adhesives and biocompatibility problems in synthetic-based adhesives. At this point, we aimed to remove all these disadvantages and produce a single adhesive that contains all the necessary features and acrylate functionalized UV-curable polyurethane formulations were produced with high crosslink density, high adhesion strength, biocompatibility and injectable property for easy application as potential biomedical adhesives. Aliphatic isophorone diisocyanate (IPDI) was used as the isocyanate source and beta-cyclodextrin was used for host-guest relationship with gentamicin by crosslinking. Proteins (gelatin (GEL), collagen (COL)) and PEGs of various molecular weight ranges (P200, P400, P600) were selected as the polyol backbone for polyurethane synthesis due to their multiple biological activities such as biocompatibility, biodegradability, biomimetic property. Several techniques have been used to characterize the structural, thermal, morphological, and various other physicochemical properties of the adhesive formulations. Besides, the possibility of its use as a hard tissue adhesive was investigated by evaluating the tissue adhesion strength in vitro and ex vivo via a universal testing analyzer in tensile mode. Corresponding adhesive formulations were evaluated by in vitro and in vivo techniques for biocompatibility. The best adhesion strength results were obtained as 3821.0 +/- 214.9, and 3722.2 +/- 486.8 kPa, for IPDI-COL-P200 and IPDI-GEL-P200, respectively. Good antibacterial activity capability toward Escherichia coli Pseudomonas aeruginosa, and Staphylococcus aureus were confirmed using disc diffusion method. Moreover, cell viability assay demonstrated that the formulations have no significant cytotoxicity on the L929 fibroblast cells. Most importantly, we finally performed the in vivo biodegradability and in vivo biocompatibility evaluations of the adhesive formulations on rat model. Considering their excellent cell/tissue viability, fast curable, strong adhesion, high antibacterial character, and injectability, these adhesive formulations have significant potential for tissue engineering applications.Öğe Preparation of mesoporous carbon containing Polyurethane/Clay nanocomposite membrane based sensors for sensitive and selective determination of vitamin D2 in urine samples(Elsevier Sci Ltd, 2022) Savan, Ebru Kuyumcu; Ozcan, Imren; Koytepe, SuleymanMesoporous carbon containing polyurethane/clay membrane based sensors were produced for the rapid and sensitive electroanalytical determination of fat-soluble vitamin D2. Mesoporous carbon structures were prepared by the carbonization of bee pollens which were easily available in nature. These structures were combined with clay and polyurethane structures. The determination of vitamin D2 with modified electrodes was carried out by using square wave voltammetry in acetonitrile containing 0.1 M LiClO4. According to the response of modified electrode, a linear relationship was obtained between the anodic oxidation peak currents and concentrations of vitamin D2 in the linear concentration range (23 mu M - 844 mu M) with a low detection limit (0.73 mu M) was obtained. The sensitivity (4.65 mu A cm- 2 mu M- 1) and reproducibility (RSD%, 1.87 %) of the prepared novel sensor were found to be quite satisfactory. The proposed method and applicability of the electrode were tested in urine samples, achieving dramatic recovery values (99.99 %).Öğe Preparation of pyridoxine-based polyurethane modified sensors and their use in simultaneous determination of Cu(II) - Co(II) ions(Elsevier, 2024) Savan, Ebru Kuyumcu; Kazici, Dilek; Ozcan, Imren; Bayram, Songuel; Koytepe, SueleymanIn this study, pyridoxine-based polyurethane-modified electrodes were prepared to simultaneously and sensitively measure copper (Cu(II)) and cobalt (Co(II)) ions in complex matrix samples. For the production of the electrodes, firstly, the synthesis of pyridoxine-based polyurethane structures was carried out. In these syntheses, the polymer structure was diversified by using different isocyanates. Polyethyleneglycol-200 (PEG), pyridoxine (B6), and beta- cyclodextrin ( beta- CD) groups were used as the source of polyol. The synthesized polyurethane structures were characterized by different instrumental techniques and used in gold electrode surface modification. Modified sensor surfaces were examined by scanning electron microscopy and atomic force microscopy techniques. The prepared modified sensors were used for the simultaneous detection of Cu(II) and Co(II) ions using the differential pulse voltammetry technique. The limit of detection (LOD), limit of quantitation (LOQ), and R 2 values for Cu(II) ions were calculated as 8.81 mu M, 29.4 mu M, and 0.993, respectively. LOD, LOQ, and R 2 values for Co(II) ions were calculated as 9.84 mu M, 32.8 mu M, and 0.9935, respectively. For repeatability, the relative standard deviation (RSD %) of the prepared simultaneous sensors was determined as 1.54 and 1.71 for Cu(II) and Co(II), respectively. As a result, Cu(II) and Co(II) ions were measured independently and simultaneously with high sensitivity. According to these results, it is predicted that pyridoxine-based polyurethane-modified sensors may be suitable for the simultaneous detection of Cu(II) and Co(II) in medical, food, and agricultural samples.Öğe Simultaneous Electrochemical Detection of Estradiol and Testosterone Using Nickel Ferrite Oxide Doped Mesoporous Carbon Nanocomposite Modified Sensor(Electrochemical Soc Inc, 2020) Tanrikut, Emrullah; Ozcan, Imren; Sel, Evren; Koytepe, Sueleyman; Savan, Ebru KuyumcuEstradiol levels in women are related to lung, uterine (endometrial), ovarian and breast cancers, although the exact mechanism of cancer development is not fully understood. A new cost-effective sensor was fabricated by incorporating conductive NiFe2O4 metal oxide into the electrochemical sensitive platform of mesoporous carbon (MC) derived from cotton to measure estradiol determination by electrochemical methods. A new modified GCE/NiFe2O4-MC electrode, which exhibits electrocatalytic activities, was created by dropping NiFe2O4-MC onto the glassy carbon electrode (GCE) surface using the drop casting technique to detect the electroactive estradiol molecule. Estradiol was determined electrochemically by using the square wave voltammetry technique with a detection limit of 6.88 nM in 20.0-566 nM linear range in phosphate buffer solution at pH 7.4 with this novel modified GCE/NiFe2O4-MC electrode, that has the best electron transfer rate. The simultaneous determination of estradiol in the presence of testosterone was successfully performed in 0.1 M tetrabutylammonium tetrafluoroborate supportive electrolyte solution prepared in acetonitrile, an anhydrous medium. Real sample applications were carried out to prove the applicability and precision of the novelty-produced electrode. The amount of estradiol in tablet samples was obtained satisfactorily with high recovery values by standard addition method. (C) 2020 The Electrochemical Society (ECS). Published on behalf of ECS by IOP Publishing Limited.Öğe The Toxicity Assessment of Iron Oxide (Fe3O4) Nanoparticles on Physical and Biochemical Quality of Rainbow Trout Spermatozoon(Mdpi, 2018) Ozgur, Mustafa Erkan; Ulu, Ahmet; Balcioglu, Sevgi; Ozcan, Imren; Koytepe, Suleyman; Ates, BurhanThe aim of this study was to evaluate the in vitro effect of different doses (50, 100, 200, 400, and 800 mg/L) of Fe3O4 nanoparticles (NPs) at 4 degrees C for 24 h on the kinematics of rainbow trout (Oncorhynchus mykiss, Walbaum, 1792) spermatozoon. Firstly, Fe3O4 NPs were prepared at about 30 nm from Iron (III) chloride, Iron (II) chloride, and NH3 via a co-precipitation synthesis technique. Then, the prepared Fe3O4 NPs were characterized by different instrumental techniques for their chemical structure, purity, morphology, surface properties, and thermal behavior. The size, microstructure, and morphology of the prepared Fe3O4 NPs were studied by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) spectroscopy, and scanning electron microscopy (SEM) equipped with an energy-dispersive X-ray spectrometer (EDS). The thermal properties of the Fe3O4 NPs were determined with thermogravimetric analysis (TGA), differential thermal analysis (DTA), and differential scanning calorimeter (DSC) analysis techniques. According to our results, there were statistically significant (p < 0.05) decreases in the velocities of spermatozoon after treatment with 400 mg/L Fe3O4 NPs. The superoxide dismutase (SOD) and catalase (CAT) activities were significant (p < 0.05) decrease after 100 mg/L in after exposure to Fe3O4 NPs in 24 h. As the doses of Fe3O4 NPs increases, the level of malondialdehyde (MDA) and total glutathione (tGSH) significantly (p < 0.05) increased at doses of 400 and 800 mg/L.Öğe Tuning electronic properties of hydroxyapatite through controlled doping using zinc, silver, and praseodymium: A density of states and experimental study(Elsevier Sci Ltd, 2024) Sahin, Binnur; Ates, Tankut; Acari, Idil Karaca; Barzinjy, Azeez A.; Ates, Burhan; Ozcan, Imren; Bulut, NiyaziThis study presents a comprehensive exploration of the electronic properties of hydroxyapatite (HA) doped with zinc (Zn), silver (Ag), and praseodymium (Pr). Five distinct compositions-0.4Pr-HA, 0.4Zn-0.4Pr-HA, 0.8Zn0.4Pr-HA, 0.4Ag-0.4Pr-HA, and 0.8Zn-0.4Pr-HA were systematically investigated through Density of States (DOS) and band structure calculations. The computed band gap values, ranging from 4.4037 to 4.1554 eV, revealed a progressive decrease in band gap energy from 0.4Pr-HA to 0.8Ag-0.4Pr-HA, emphasizing the substantial impact of dopant composition on electronic properties. Additionally, the incorporation of Pr induced distinct bands and peaks in the density of states, signifying the emergence of specific energy levels associated with Pr and suggesting a clear effect on the electronic structure. Furthermore, the study explores the influences of dopant type and quantity on the electronic structure, microstructure, spectral, thermal, and in vitro cell viability properties of Pr-based HA samples. Theoretical results demonstrated a continuous decrease in the bandgap with Ag or Zn dopants, and the study observed controllable changes in LAC values based on co-dopant type and quantity. Experimental outcomes revealed significant effects on crystallinity, crystallite size, lattice parameters, and unit cell volume, confirmed through XRD, SEM, EDX, FTIR, and Raman analyses. These findings provide valuable visions into the tunability of the electronic properties of HA through controlled doping with Zn, Pr, and Ag. This knowledge is crucial for modifying materials with desirable electronic properties, and thus holds promise for various applications in electronic devices and biocompatible coatings.
