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Öğe Combined voltammetric and spectroscopic investigation of binding interaction between nifedipine and human serum albumin on polyelectrolyte modified ITO electrode(PERGAMON-ELSEVIER SCIENCE LTD, 2013) Ozmen, Mustafa; Maltas, Esra; Patir, Imren Hatay; Bayrakci, MevlutThe binding interaction between the drug molecule, nifedipine (Nf), and the human serum albumin (HSA) on polyelectrolyte modified indium tin oxide (ITO) electrode has been investigated by the combination of electrochemical and fluorescence spectroscopy techniques. Surface modification has also been characterized by scanning electron microscopy (SEM) and Contact Angle (CA) measurements in each step. The cyclic voltammetry, electrochemical impedance parameters (peak potential difference (Delta E-p)), peak current difference (Delta I-p) and charge-transfer resistance (R-ct) indicate that nifedipine strongly interacted with human serum albumin molecule on the polyelectrolyte modified ITO electrode surface. Stern-Volmer quenching constant K-a is inversely correlated with the temperature, which indicates that the probable quenching mechanism of the nifedipine-human serum albumin binding reaction is initiated by complex formation. The results obtained from these techniques showed that Nf could bind to HSA. The binding constant (K-b) and the number of binding sites (n) of the drug with HSA at different temperatures were determined. At 298 K, K-b was found as 4.04 x 10(-3) and n was 1.08 for Nf-HSA. According to the van't Hoff equation, the thermodynamic parameters, Delta G, Delta H and Delta S, were obtained, showing the involvement of hydrophobic and electrostatic force in this interaction. (C) 2013 Elsevier Ltd. All rights reserved.Öğe Development of New Fluorescent Dyes by Using Amine Modified Nanoparticles for Immunostaining(TAYLOR & FRANCIS INC, 2016) Maltas, Esra; Ozmen, Mustafa; Ucan, H. IsmetFluorescent labeling of DNA was studied by using two newly synthesized ligands, which are 4-(2-hydroxybenzylidinamino) benzoic acid (PHBA) and 4-(2-hydroxybenzylidinamino) phthalic acid (PHPA). Their binding capacity to calf-thymus DNA was determined on functionalized superparamagnetic iron oxide nanoparticles (SPIONs). 23.1 mu g of DNA was immobilized on 25mg of nanoparticles. Binding capacity of fluorescent ligands to DNA-APTS-SPIONs was also found as 2.36 mu M for PHBA and 1.97 for PHPA at 25mg of the nanoparticles. Binding of the DNA to the ligands were examined by scanning electron microscopy, transmission electron microscopy, infrared spectroscopy, and confocal microscopy.Öğe Electrochemical H2O2 Sensor Based on Graphene Oxide-Iron Oxide Nanoparticles Composite(IEEE, 2017) Bas, Salih Zeki; Ozmen, Mustafa; Yildiz, SalihThis study presents hydrogen peoxide determination using a new electrochemical sensor based on Fe3O4 functionalized graphene oxide (Fe3O4-APTES-GO). Fe3O4-APTES-GO was synthesized by a two-step process. First, Fe3O4 was modified by (3-aminopropyl) triethoxysilane to introduce amino groups on the surface of graphene oxide(GO). Second, APTES-Fe3O4 was reacted with the carboxylic groups of GO by an activating agent N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride to form a new material called as Fe3O4-APTES-GO. The electrocatalytic activity of Fe3O4-APTES-GO towards electrooxidation of H2O2 was described by using cyclic voltammetry technique.Öğe Fluorescent labelling of DNA on superparamagnetic nanoparticles by a perylene bisimide derivative for cell imaging(ELSEVIER SCIENCE BV, 2015) Maltas, Esra; Malkondu, Sait; Uyar, Pembegul; Ozmen, MustafaN,N'-Bis[tris-(2-aminoethyl) amine]-3,4,9,10-perylenetetracarboxylic diimide (PBI-TRIS), nonfluorescent dye was used to fluorescent labelling of DNA. For this aim, (3-aminopropyl) triethoxysilane (APTS) modified superparamagnetic iron oxide nanopartides (SPIONs) were synthesized to provide a suitable surface for binding of DNA. Amine functionalized nanoparticles showed a high immobilization capacity (82.70%) at 25 mg of nanoparticle concentration for Calf thymus DNA. Binding capacity of PBI-TRIS to DNA-SPION was also found as 1.93 mu M on 25 mg of nanoparticles by using UV-vis spectroscopy. Binding of PBI-TRIS to DNA onto nanoparticles was also characterized by scanning electron microscopy and infrared spectroscopy. The confocal images of PBI-TRIS labelled DNA-SPION and breast cells were taken at 488 and 561.7 nm of excitation wavelengths. Cell image was also compared with a commercial dye, DAPI at 403.7 nm of excitation wavelength. Results showed that PBI-TRIS can be used for cell staining. (C) 2014 Elsevier B.V. All rights reserved.Öğe Functionalization of whole-cell bacterial reporters with magnetic nanoparticles(WILEY, 2011) Zhang, Dayi; Fakhrullin, Rawil F.; Ozmen, Mustafa; Wang, Hui; Wang, Jian; Paunov, Vesselin N.; Li, GuangheWe developed a biocompatible and highly efficient approach for functionalization of bacterial cell wall with magnetic nanoparticles (MNPs). Three Acinetobacter baylyi ADP1 chromosomally based bioreporters, which were genetically engineered to express bioluminescence in response to salicylate, toluene/xylene and alkanes, were functionalized with 18 +/- 3 nm iron oxide MNPs to acquire magnetic function. The efficiency of MNPs functionalization of Acinetobacter bioreporters was 99.96 +/- 0.01%. The MNPs-functionalized bioreporters (MFBs) can be remotely controlled and collected by an external magnetic field. The MFBs were all viable and functional as good as the native cells in terms of sensitivity, specificity and quantitative response. More importantly, we demonstrated that salicylate sensing MFBs can be applied to sediments and garden soils, and semi-quantitatively detect salicylate in those samples by discriminably recovering MFBs with a permanent magnet. The magnetically functionalized cells are especially useful to complex environments in which the indigenous cells, particles and impurities may interfere with direct measurement of bioreporter cells and conventional filtration is not applicable to distinguish and harvest bioreporters. The approach described here provides a powerful tool to remotely control and selectively manipulate MNPs-functionalized cells in water and soils. It would have a potential in the application of environmental microbiology, such as bioremediation enhancement and environment monitoring and assessment.Öğe ILEUS DUE TO EXTENSIVE AIR INSUFFLATION WITH ENDOSCOPIC RETROGRADE CHOLANGIO-PANCREATOGRAPHY(LIPPINCOTT WILLIAMS & WILKINS, 2017) Yilmaz, Bulent; Aksoy, Evrim; Koklu, Seyfettin; Ozmen, Mustafa[Abstract not Available]Öğe Interaction Between Ketoconazole and Human Serum Albumin on Epoxy Modified Magnetic Nanoparticles for Drug Delivery(AMER SCIENTIFIC PUBLISHERS, 2013) Maltas, Esra; Ozmen, Mustafa; Yildirimer, Burak; Kucukkolbasi, Semahat; Yildiz, SalihSuperparamagnetic iron oxide nanoparticles (SPIONs) were modified with [3-(2,3-epoxypropoxy)propyl] trimethoxy silane, which resulted in formation of epoxy groups on the particles surface. The epoxy functionalized SPIONs can bind to human serum albumin (HSA). The binding amount of HSA to epoxy modified SPIONs was found to be as 32.7 mu M for 1 mg epoxy modified SPIONs at 280 and 342 nm of excitation and emission wavelengths by using fluorescence spectroscopy. Interaction of ketoconazole with HSA immobilized epoxy functionalized SPIONs was studied at 300 and 390 nm of excitation and emission wavelengths, respectively. Binding mechanism of ketoconazole and HSA was identified by Stern-Volmer equation. Thermodynamic parameters (Delta H, Delta S and Delta G) were also estimated for the interaction. Therefore, the nature of the binding forces was found to be as hydrophobic interaction. Protein and drug attachments were also examined by Infrared spectroscopy (IR) and Scanning Electron Microscopy (SEM). This study show that prepared albumin-based magnetic nanoparticles carrier systems represents an attractive strategy for drug delivery.Öğe Interaction of donepezil with human serum albumin on amine-modified magnetic nanoparticles(ELSEVIER SCIENCE BV, 2014) Buzoglu, Leman; Maltas, Esra; Ozmen, Mustafa; Yildiz, SalihThe interaction between the drug donepezil and human serum albumin (HSA) was examined on the surface of amine modified superparamagnetic iron oxide nanoparticles (SPIONs), which were synthesized by the coprecipitation of ferrous and ferric salts with NH4OH and then modified with [3-Aminopropyl] triethoxysilane (APTES) to obtain functional amine groups on the nanoparticles' surface. Albumin's binding capacity to APTES-modified SPIONs was estimated by fluorescence spectroscopy. After HSA was bound to the APTES modified SPIONs, donepezil was interacted with the HSA-SPIONs. The binding capacity of the drug was determined using a calibration curve equation that was drawn using fluorescence spectroscopy at 325 and 387 nm, the excitation and emission wavelengths. Thermodynamic parameters were estimated for the interaction of HSA and donepezil on amine-modified SPIONs. Binding was carried out spontaneously via electrostatic interaction. Binding was also examined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SOS-PAGE), scanning electron microscopy (SEM) and zeta-potential measurements. (C) 2013 Elsevier B.V. All rights reserved,Öğe Interaction of L-myc oncogene in breast cancer with irinotecan onto functionalized magnetic nanoparticles(ELSEVIER SCIENCE BV, 2013) Maltas, Esra; Ozmen, Mustafa; Vural, Hasibe CingilliThe effect of different functional groups on binding capacity of DNA was studied with bare and modified superparamagnetic iron oxide nanoparticles (SPIONs). For this purpose, modifications were performed with [3(2,3-epoxypropoxy)propyl] trimethoxy silane (GPTS) and (3-aminopropyl) triethoxysilane (APTS) by silanization reaction and also subsequent reaction with glutaraldehyde (GA) to obtain functional groups on nanoparticles surface. L-myc gene from breast tissue with cancer was amplified by using polymerase chain reaction (PCR). APTS functionalized nanoparticles showed the highest binding capacity (82.70%) when compared with bare, GPTS, APTS and GA functionalized SPIONs. DNA immobilized magnetic nanoparticles were also examined by Scanning Electron Microscopy. Binding capacity of irinotecan to DNA onto SPIONs was found as 2.81 x 10(-5) mg/mL for 20 mg of APTS modified nanoparticles by using fluorescence spectroscopy. (C) 2013 Elsevier B.V. All rights reserved.Öğe Magnetic nanoparticles-serum proteins bioconjugates for binding of irinotecan(ELSEVIER, 2015) Tamyurek, Ecem; Maltas, Esra; Bas, Salih Zeki; Ozmen, Mustafa; Yildiz, SalihThe binding of irinotecan to serum proteins (hemoglobin, globulin and human serum albumin) was studied on the surface of epoxide modified superparamagnetic iron oxide nanoparticles (GPT'S-SPIONs), which were synthesized by the coprecipitation of ferrous and ferric salts with NH4OH and then modified with [3-(2,3-epoxypropoxy)propyl] trimethoxy silane (GPTS) to obtain functional epoxide groups on the SPIONs' surface. Results were compared to find an alternative as drug carries system. Data showed that binding amount of human serum albumin (HSA), globulin (Gib) and hemoglobin (Hb) found to be as 44, 21.2 and 32.6 mu g per 20 mg of GPTS modified SPIONs, respectively. The thermal behavior of the serum protein-Ir interaction on GPTS-SPIONs was also studied by using thermo gravimetric analysis (TGA) technique and then the kinetic parameters for the thermal decomposition were determined using Horowitz-Metzger method. (C) 2014 Elsevier B.V. All rights reserved.Öğe Molecularly Functionalized Silicon Substrates for Orientation Control of the Microphase Separation of PS-b-PMMA and PS-b-PDMS Block Copolymer Systems(AMER CHEMICAL SOC, 2013) Borah, Dipu; Ozmen, Mustafa; Rasappa, Sozaraj; Shaw, Matthew T.; Holmes, Justin D.; Morris, Michael A.The use of block copolymer (BCP) thin films to generate nanostructured surfaces for device and other applications requires precise control of interfacial energies to achieve the desired domain orientation. Usually, the surface chemistry is engineered through the use of homo- or random copolymer brushes grown or attached to the surface. Herein, we demonstrate a facile, rapid, and tunable approach to surface functionalization using a molecular approach based on ethylene glycol attachment to the surface. The effectiveness of the molecular approach is demonstrated for the microphase separation of PS-b-PMMA and PS-b-PDMS BCPs in thin films and the development of nanoscale features at the substrate.Öğe A new BODIPY/nanoparticle/Ni affinity system for binding of cytochrome c(ELSEVIER SCIENCE BV, 2015) Maltas, Esra; Kursunlu, Ahmed Nuri; Arslan, Gulsin; Ozmen, MustafaIn this study, 3,5-{Bis[4,4-difluoro, 8-(2,6-diethyl, 1,3,5,7-tetramethy1-4-bora-3a,4a-diaza-sindacene)]}benzoylchloride (BODIPY) was synthesized for the improving of a new immobilized metal affinity supporting material. Firstly, the synthesized BODIPY was immobilized on iron oxide superparamagnetic nanoparticles (SPIONs) and then, Ni(II) ions were chelated with the active terminals of BODIPY on nanoparticles surfaces to prepare an immobilized metal affinity (IMA) adsorbent for protein adsorption. The amount of BODIPY coated on SPIONs was about 29.7 mu M at 10 mg nanoparticles. 738 mu mol of Ni(II) ions were loaded to 10 mg of the SPIONs/BODIPY. The binding amount of cytochrome c was found to be 170 mu g to the SPIONs/BODIPY/Ni at pH 7.4. The binding amount of the molecules on SPIONs was analyzed by using UV-vis, fluorescence and atomic absorption spectroscopy. The characterization of the prepared surfaces was performed by FT-IR, SEM and TEM. (C) 2015 Elsevier B.V. All rights reserved.Öğe A new electrochemical sensor based on Fe3O4 functionalized graphene oxide-gold nanoparticle composite film for simultaneous determination of catechol and hydroquinone(PERGAMON-ELSEVIER SCIENCE LTD, 2015) Erogul, Seyma; Bas, Salih Zeki; Ozmen, Mustafa; Yildiz, SalihCatechol (1,2-dihydroxybenzene) and hydroquinone (1,4-dihydroxybenzene) are two isomers of phenolic compounds which often coexist and interfere with each other during their identification in environmental samples. This study presents simultaneous determination of catechol (CC) and hydroquinone (HQ) using a new electrochemical sensor based on Fe3O4 functionalized graphene oxide-gold nanoparticle composite (AuNPs/Fe3O4-APTES-GO). CV results show well-defined oxidation peaks with anodic peaks at 0.15 V for CC and 0.05 V for HQ, and the peak-to-peak separation for CC and HQ is about 100 mV. Under the optimized conditions, the current response of AuNPs/Fe3O4-APTES-GO/GCE is linear for CC and HQ in the range of 2-145 mu M and 3-137 mu M, respectively. The detection limits for CC and HQ were found to be 0.8 mu M and 1.1 mu M, respectively. The fabricated sensor was successfully applied for the determination of CC and HQ in tap water sample with satisfactory recovery. (C) 2015 Elsevier Ltd. All rights reserved.Öğe A Novel Electrochemical Sensor Based on Metal Ion Infiltrated Block Copolymer Thin Films for Sensitive and Selective Determination of Dopamine(AMER CHEMICAL SOC, 2019) Bas, Salih Zeki; Cummins, Cian; Selkirk, Andrew; Borah, Dipu; Ozmen, Mustafa; Morris, Michael A.An electrochemical sensor using copper oxide nanodots (CuO nanodots-ITO) developed from a block copolymer template is demonstrated for sensitive and selective determination of dopamine (DA). The current signal of CuO nanodots-ITO was linear with the concentration of DA in the range between 0.12 and 56.87 mu M (R = 0.9975) with a sensitivity of 326.91 mu A mM(-1) cm(-2) and a detection limit of 0.03 mu M. Furthermore, the anti-interference ability of the present sensor to possible interfering substances including ascorbic acid, uric acid, acetaminophen, epinephrine, hydrogen peroxide, phenol, catechol, hydroquinone, and some inorganic compounds has been investigated. Our work highlights the significance of using a bottom-up nanofabrication technique to create a robust and reliable dopamine sensor that has critical importance in neurological disorders.Öğe Novel humic acid-bonded magnetite nanoparticles for protein immobilization(ELSEVIER SCIENCE BV, 2014) Bayrakci, Mevlut; Gezici, Orhan; Bas, San Zeki; Ozmen, Mustafa; Maltas, EsraThe present paper is the first report that introduces (i) a useful methodology for chemical immobilization of humic acid (HA) to aminopropyltriethoxysilane-functionalized magnetite iron oxide nanoparticles (APS-MNPs) and (ii) human serum albumin (HSA) binding to the obtained material (HA-APS-MNPs). The newly prepared magnetite nanoparticle was characterized by using Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and elemental analysis. Results indicated that surface modification of the bare magnetite nanoparticles (MNPs) with aminopropyltriethoxysilane (APS) and HA was successfully performed. The protein binding studies that were evaluated in batch mode exhibited that HA-APS-MNPs could be efficiently used as a substrate for the binding of HSA from aqueous solutions. Usually, recovery values higher than 90% were found to be feasible by HA-APS-MNPs, while that value was around 2% and 70% in the cases of MNPs and APS-MNPs, respectively. Hence, the capacity of MNPs was found to be significantly improved by immobilization of HA. Furthermore, thermal degradation of HA-APS-MNPs and HSA bonded HA-APS-MNPs was evaluated in terms of the Horowitz-Metzger equation in order to determine kinetic parameters for thermal decomposition. Activation energies calculated for HA-APS-MNPs (20.74 kJ mol(-1)) and HSA bonded HA-APS-MNPs (33.42 kJ mol(-1)) implied chemical immobilization of HA to APS-MNPs, and tight interactions between HA and HA-APS-MNPs. (C) 2014 Elsevier B.V. All rights reserved.Öğe Novel magnetite nanoparticle based on BODIPY as fluorescent hybrid material for Ag(I) detection in aqueous medium(ELSEVIER, 2016) Kursunlu, Ahmed Nuri; Ozmen, Mustafa; Guler, ErsinThis manuscript describes a highly selective and ultra-sensitive detection of Ag(l) in aqueous solution using amine coated magnetite nanoparticles modified boron-dipyrromethene by spectrofluorometer. Fe3O4 nanoparticles were synthesized by co-precipitation of Fe2+ and Fe(3+)in an ammonia solution. Amine modified Fe3O4 was prepared by using (3-aminopropyl)triethoxysilane as silanization agent. The covalent binding of boron-dipyrromethene to amine modified Fe3O4 was confirmed by means of Fourier Transform infrared spectroscopy, transmission electron microscopy, dynamic light scattering, UV-vis and fluorimeter measurements and obtained nanoparticle-boron dipyrromethene structure. The binding abilities of nanoparticle-boron dipyrromethene towards different metal ions have been investigated by some spectroscopic methods as UV-vis, fluorescence spectroscopy, Job plot, etc. and the novel surface displayed high selectivity and sensitivity for Ag(I) among all tested metals. (C) 2016 Elsevier B.V. All rights reserved.Öğe Preparation of pillar[5]arene immobilized trypsin and its application in microwave-assisted digestion of Cytochrome c(ELSEVIER SCIENCE BV, 2019) Atacan, Keziban; Kursunlu, Ahmed Nuri; Ozmen, MustafaThis work presents the immobilization of trypsin on the synthesized pillar[5]arene derivative (P5) containing ten iodo-terminals. The characterization has been carried out by Thermogravimetric Analysis (TGA), Fourier Transform Infrared (FTIR) and Raman spectra, Scanning Electron Microscopy (SEM) and Zeta Potential. Furthermore, Cytochrome c (Cyt c) was chosen as a model protein for evaluation of the performance of the pillar [5]arene-immobilized trypsin (P5-T), and its microwave-assisted digestion conditions were investigated by using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) for 15 second. The peptide numbers of 10 and sequence coverage of 93% for 15 second microwave-assisted digestion were obtained for P5-T. The results can be further applied in future proteomics studies due to high efficiency, good reproducibility and stability of the pillar[5]arene-immobilized trypsin.Öğe Spectrofluorometric and thermal gravimetric study on binding interaction of thiabendazole with hemoglobin on epoxy-functionalized magnetic nanoparticles(ELSEVIER, 2015) Maltas, Esra; Ozmen, MustafaThe interaction of thiabendazole (Tbz) with hemoglobin (Hb) on epoxy-functionalized iron oxide nanoparticles was presented in this study. The binding capacity of Tbz was determined by measuring at an excitation wavelength of 299 nm using fluorescence spectroscopy. The thermodynamic parameters of the Hb-Tbz interaction were calculated from Stern-Volmer and van't Hoff equations. The values of enthalpy change, Delta H, and entropy change,.Delta S, were found to be 0.20 kJ mol(-1) and 0.70 J mol(-1) K-1, respectively, which indicates that the hydrophilic interaction plays a main role in the binding process. The interaction ability was confirmed by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Also, the thermal behavior of the Hb-Tbz interaction on functionalized iron oxide nanoparticles was studied by using the thermogravimetric analysis (TGA) technique in the temperature range of 25-950 degrees C, and then the kinetic parameters for the thermal decomposition were determined using the Horowitz-Metzger method. (C) 2015 Elsevier B.V. All rights reserved.Öğe Surface modification of glass beads with an aminosilane monolayer(SCIENTIFIC TECHNICAL RESEARCH COUNCIL TURKEY-TUBITAK, 2006) Arslan, Gulsin; Ozmen, Mustafa; Gunduz, Beniz; Zhang, Xunli; Ersroz, MustafaSurface modification of glass beads with a self-assembled monolayer of (3-Aminopropyl)-triethoxysilane (APTES) was investigated. Characterisation of the self-assembled monolayer was confirmed by a reaction between amine terminal groups and thionylchloride of Rhodamine-B dye using fluorescence microscopy. Quantitative 3-dimensional profiling was obtained for all modification processes by converting microscopic images to numerical values. The reaction steps were also analysed using infrared spectroscopy (FTIR).Öğe Synthesis and application of novel magnetite nanoparticle based azacrown ether for protein recognition(POLYMER SOC KOREA, 2013) Bayrakci, Mevlut; Maltas, Esra; Yigiter, Sengul; Ozmen, MustafaThis article is the first report showing the human serum albumin (HSA) binding studies by using a new magnetite nanoparticle containing azacrown ether moieties via solid-liquid extraction process. The structure of the newly prepared magnetite nanoparticle was clarified by using attenuated total reflectance (ATR) infrared spectroscopy, scanning electron microscopy (SEM), UV-vis and elemental analysis. Analytic results indicated that modification of the surface of the magnetite nanoparticles with azacrown ether derivative was successfully carried out. The protein binding studies exhibited that the modified magnetite nanoparticles could be efficiently used for the binding of the human serum albumin (HSA) in aqueous solutions via non-covalent interaction between crown ether cavity and amino group of the protein.
