Yazar "Uzun, Lokman" seçeneğine göre listele
Listeleniyor 1 - 19 / 19
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe A novel magnetic Fe@Au core-shell nanoparticles anchored graphene oxide recyclable nanocatalyst for the reduction of nitrophenol compounds(Pergamon-Elsevier Science Ltd, 2014) Gupta, Vinod Kumar; Atar, Necip; Yola, Mehmet Lutfi; Ustundag, Zafer; Uzun, LokmanIn this study, a novel catalyst based on Fe@Au bimetallic nanoparticles involved graphene oxide was prepared and characterized by transmission electron microscope (TEM), and x-ray photoelectron spectroscopy (XPS). The nanomaterial was used in catalytic reductions of 4-nitrophenol and 2-nitrophenol in the presence of sodium borohydride. The experimental parameters such as temperature, the dosage of catalyst and the concentration of sodium borohydride were studied. The rates of catalytic reduction of the nitrophenol compounds have been found as the sequence: 4-nitrophenol>2-nitrophenol. The kinetic and thermodynamic parameters of nitrophenol compounds were determined. Activation energies were found as 2.33 kcal mol(-1) and 3.16 kcal mol(-1) for 4-nitrophenol and 2-nitrophenol, respectively. The nanomaterial was separated from the product by using a magnet and recycled after the reduction of nitrophenol compounds. The recyclable of the nanocatalyst is economically significant in industry. (C) 2013 Elsevier Ltd. All rights reserved.Öğe A porous molecularly imprinted nanofilm for selective and sensitive sensing of an anticancer drug ruxolitinib(Elsevier, 2021) corman, M. Emin; Cetinkaya, Ahmet; Ozcelikay, Goksu; Ozgur, Erdogan; Atici, Esen B.; Uzun, Lokman; Ozkan, Sibel A.A novel methodology has been applied to generate a porous molecularly imprinted material for highly selective and sensitive recognition of Janus kinase inhibitor ruxolitinib (RUX). The porous material-based nucleobase-derivative functional monomer was developed by a photopolymerization method. The thymine methacrylate (ThyM) as a functional monomer was synthesized and copolymerized with 2hydroxyethyl methacrylate (HEMA) in the presence of ethylene glycol dimethacrylate (EGDMA) onto the glassy carbon electrode [glassy carbon electrode/molecularly imprinted polymer@poly(2hydroxyethyl methacrylate-co-thymine methacrylate), (GCE/MIP@PHEMA-ThyM)] for the first time. The presence of ThyM results in the functional groups in imprinting binding sites, while the presence of poly(vinyl alcohol) (PVA) allows to generate porous materials for sensitive sensing. The characterization of GCE/MIP@PHEMA-ThyM was investigated by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and impedance spectroscopy technique. Then, the porous MIP modified glassy carbon electrode was optimized with effecting parameters including removal agent, removal time, and incubation time to get a better response for RUX. Under well-controlled optimum conditions, the GCE/MIP@PHEMA-ThyM linearly responded to the RUX concentration up to 0.01 pM at the limit of detection (LOD) of 0.00191 pM. The non-imprinted polymer (NIP) was also prepared to serve as a control in the same way but without the template. The proposed method improves the accessibility of binding sites by generating the porous material resulting in highly selective and sensitive recognition of drugs in the pharmaceutical dosage form and synthetic human serum samples. (c) 2021 Elsevier B.V. All rights reserved.Öğe Composite Cryogels Having Functional Hydrophobic Groups Preparation, Characterization and Use in DNA Adsorption(12th Eurasia Conference on Chemical Sciences, 2012) Çorman, Mehmet Emin; Bereli, Nilay; Özkara, Serpil; Uzun, Lokman; Denizli, Adil[Abstract Not Available]Öğe Development of molecular imprinted nanosensor for determination of tobramycin in pharmaceuticals and foods(Elsevier Science Bv, 2014) Yola, Mehmet Lutfi; Uzun, Lokman; Ozaltin, Nuran; Denizli, AdilIn this study, we developed quartz crystal microbalance (QCM) nanosensor for the real-time detection of tobramycin (TOB). Firstly, the modification of gold surface of QCM chip was performed by self-assembling monolayer formation of allyl mercaptane to introduce polymerizable double bonds on the chip surface. Then, TOB imprinted poly(2-hydroxyethyl methacrylate-methacryloylamidoglutamic acid) [p(HEMA-MAGA)] film was generated on the gold surface. The nonmodified and TOB-imprinted p(HEMA-MAGA) surfaces were characterized by using atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectroscopy, ellipsometry and contact angle measurements. The proposed method was validated according to the ICH guideline. The linearity range and the detection limit (S/N=3) were obtained as 1.7 x 10(-11)-1.5 x 10(-10) M and 5.7 x 10(-12) M, respectively. The developed method was applied to pharmaceuticals, and food samples such as chicken egg white and milk extract for the determination of TOB. In addition, association kinetics analysis and isotherm models were applied to the data to explain the adsorption process that took place. (C) 2013 Elsevier B.V. All rights reserved.Öğe Dış Uyarıların Hücre Canlılığı ve Yayılmasına Etkisinin İncelenmesi Amacıyla Farklı Fiziksel ve Kimyasal Özelliklere Sahip Polimerik Membranların Geliştirilmesi ve Uygulamaları(2019) Çorman, Mehmet Emin; Uzun, LokmanProjede, doku mikroçevrelerinin biyokimyasal, mekanik ve topografik özelliklerini uygun şekilde taklit eden hücre tabakalarının oluşturulması için uyarı-cevap temelli biyomalzemeler geliştirilmiştir. Projein ilk aşamasında, iki tür kopolimer poly(2-hidroksi etilmetakrilat) (PHEMA)-N-metakriloil-L-glutamik asit/aspartik asit (MAGA/MAAsp) ve P(HEMA-Nizopropilakrilamit) (NIPAAm) ve üç farklı terpolimer PHEMA-MAGA-Fe3O4, PHEMA-MAGANIPAAm, PHEMA-MAGA-NIPAAm-Fe3O4 fotobaşlatıcı serbest radikal polimerizasyon yöntemiyle sentezlenmiştir. Daha sonra bu malzemeler biyotanıma elemanı olan kolajen ve hyaluronik asit ile immobilize edilmiştir. Geliştirilen hücre tabakaları, Fourier dönüşümlü infrared spektroskopi, taramalı elektron mikroskobu, termal gravimetrik analiz, çekme-uzama testi elektron spin rezonans spektroskopisi ve dinamik mekanik analiz yöntemleri kullanılarak karakterize edilmiştir. Biyolojik tanıma elemanlarının (Hyaluronik asit ve Kolajen), polimerik yapıya immobilizasyonu floresan boyama (immuno-boyama) işlemi ile takip edilmiştir. Karakterizasyon işlemleri, her modifikasyon aşamasında tekrarlanmış ve hedeflenen polimerik yapıların ve modifikasyon işlemlerinin başarıyla gerçekleştirildiği ortaya konulmuştur. Ter-polimer gruplarına ait veriler MTT değeri incelendiğinde; hücre canlılığı değerlerinin ko-polimerlere göre yaklaşık %50 daha yüksek olduğu gözlenmiştir. Bununla birlikte ter-polimer grubu için kolajen immobilizasyonu her üç grup için de hücre canlılığını olumlu yönde etkilemiştir. Bu durum, kolajen immobilizasyonunun hücre canlılığında pozitif etki gösterdiğini ortaya koymuştur. Hücre canlılığına sıcaklığın etkisi ve hücre çoğalma davranışının sıcaklık ile kontrolü amacıyla kolajen içeren membranlar üzerinde gerçekleştirilen deney grubuna ait veriler incelendiğinde artan sıcaklığın (25oC?dan 37oC?a) hücre canlılık değerinde bir artışa sebep olduğu belirlenmiştir. Manyetik alan varlığında; polimerik yapıya katkılanmış Fe3O4?lerin iç manyetik alan oluşturması ve hücrelerin yüzeye daha fazla yönlenmesiyle manyetik alanda hücre canllığı artmıştır. Diğer taraftan pH incelendiğinde ise pH değeri 7.4?den pH 6.0?ya geçildiğinde hücre canlığında azalma gözlenmiştir. Bu durum, kolajenin yapısındaki karboksili asit gruplarının protonlanması ile ilişkilendirilmiştir. Son olarak, geliştirilen polimerik membranlardan L929 hücrelerin tabaka şeklinde kaldırılmasının mümkün olduğu gösterilmiştir. Bu sistem ile geliştirilen polimerlerin dış çevrede meydana gelen değişimlere şekil değiştirerek L929 hücrelerin ayrılmasında ve kaldırılmasında etkin bir şekilde kullanılacağı belirtilmelidirÖğe Electrochemically modified sulfisoxazole nanofilm on glassy carbon for determination of cadmium(II) in water samples(Pergamon-Elsevier Science Ltd, 2013) Gupta, Vinod Kumar; Yola, Mehmet Lutfi; Atar, Necip; Solak, Ali Osman; Uzun, Lokman; Ustundag, ZaferSulfisoxazole (SO) was grafted to glassy carbon electrode (GCE) via the electrochemical oxidation of SO in acetonitrile solution containing 0.1 M tetrabutylammoniumtetra-fluoroborate (TBATFB). The prepared electrode was characterized by using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), reflection-absorption infrared spectroscopy (RAIRS) and X-ray photoelectron spectroscopy (XPS). The ellipsometric thickness of SO nanofilm at the glassy carbon surface was obtained as 14.48 +/- 0.11 nm. The stability of the SO modified GCE was studied. The SO modified GCE was also utilized for the determination of Cd(II) ions in water samples in the presence of Pb(II) and Fe(II) by adsorptive stripping voltammetry. The linearity range and the detection limit of Cd(II) ions were 1.0 x 10(-1) to 5.0 x 10(-8) M and 3.3 x 10(-11) M (S/N = 3), respectively. (C) 2013 Elsevier Ltd. All rights reserved.Öğe İnsan Sağlığı için Toksik ve Kanserojen Etkiler Olusturan Benzo[a]piren’in Tayini.(18. Biyomedikal Mühendisligi Ulusal Toplantısı, 2014) Çorman, Mehmet Emin; Armutçu, Canan; Uzun, Lokman; Denizli, AdilSunulan çalışma kapsamında, çevre sularında eser miktarlarda bulunan benzo[a]piren (BaP)’in tayini amaçlanmıştır. Çalışmanın ilk aşamasında BaP baskılanmış poli(2-hidroksietil metakrilat-N-metakriloil-Lfenilalanin) monolitik polimerler, yığın polimerizasyonu yöntemi ile sentezlenmiştir. Elde edilen monolitik polimerler, öğütülerek eş boyutlu partiküller elde edilmiştir. Öğütülen polimerler elenerek 64-71 ?m boyut aralığındaki partiküller ayrılmış ve daha sonraki işlemlerde kullanılmıştır. BaP baskılanmış kompozit kartuşlar ise BaP baskılanmış partiküllerin varlığında, 2-hidroksietil metakrilat (HEMA) ve metilen bisakrilamidin (MBAAm), -12°C’da 24 saatlik yarı-donmuş koşullar altındaki polimerizasyonu ile üretilmiştir. Kartuşlar, şişme testi, taramalı elektron mikroskobu (SEM), elementel analiz ve Fourier dönüşümlü infrared spektroskopisi (FTIR) yöntemleri ile karakterize edilmiştir. Hazırlanan kompozit kartuşlar, sulu çözeltilerden BaP ön-deriştirme işlemlerinde kullanılmış ve ön-deriştirme koşulları optimize edilmiştir. Optimizasyon çalışmaları kapsamında; BaP derişimi, pH, santrifüj hızı, sıcaklık, iyonik şiddet, monomer oranı ve partikül miktarının etkileri incelenmiştir. Kompozit kartuşların diğer polisiklik aromatik hidrokarbon (PAH) türlerine karşı seçicilikleri, benzo[b]floranten (BbF), benzo[k]floranten (BkF), indeno[1,2,3-cd]piren (IcdP) ve 1-naftol varlığında gerçekleştirilen seçicilik çalışmaları ile belirlenmiştir.Öğe Interface imprinted polymers with well-oriented recognition sites for selective purification of hemoglobin(Elsevier, 2021) Armutcu, Canan; Ozgur, Erdogan; Corman, M. Emin; Uzun, LokmanIn this study, we introduced a new strategy to design interface imprinted polymers for a novel aspect of molecular imprinting technique, utilization of sacrificial metal oxide particles. In the first step, bovine hemoglobin (BHb) was adsorbed on zinc oxide (ZnO) particles, which were then used to synthesize polyacrylic acid-based molecular imprinting membrane by bulk polymerization in the presence of ethylene glycol dimethacrylate as a cross-linking agent. After polymerization terminated, BHb-ZnO particles were removed to leave effective imprint sites onto the bulk polymeric network which is responsible for the formation of template orientation. The characterization of membranes was investigated by using Fourier transform infrared (FTIR), Raman spectroscopy (RS), scanning electron microscopy (SEM), surface area measurements (BET analyses) and thermogravimetric analysis (TGA). The interface molecularly imprinted membranes (iMIMs) have a relatively high specific rebinding capacity of 65.98 mg/g and excellent selectivity towards BHb with a separation factor of 6.78. The equilibrium adsorption isotherms fitted well to Langmuir isotherms (R-2 = 0.9944) and the value of adsorption capability (Q(max)) and equilibrium constant (b) were estimated to be 73.53 mg/g and 1.36 mg/mL for the iMIM, respectively. The kinetics of adsorption fitted best to pseudo-second order (R-2 = 0.9912). The ZnO particles were used not only to ensure the preservation of the imprint cavities in the polymer network but also to lead to high template removal and better rebinding kinetics. This novel design with multiple recognition sites is quite simple and suitable for the separation of biomacromolecules.Öğe Lysine Imprinted Nanoparticles for Antibody Biorecogniton(2-nd International Conference Nanomaterials: Applications & Properties- Vol. 1 No 2, 02NNBM21(2pp), 2012) Çorman, Mehmet Emin; Armutçu, Canan; Uzun, Lokman; Say, Rıdvan; Denizli, AdilThe aim of this study was to prepare L-lysine-imprinted poly(HEMA-MAAsp) nanoparticles which can be used for the adsorption of IgG from aqueous solutions. L-lysine was complexed with MAAsp and Llysine- imprinted poly(HEMA-MAAsp) nanoparticles were synthesized by miniemulsion polymerization. Also, non-imprinted nanoparticles were synthesized without L-lysine for control purpose. L-lysine-imprinted poly(HEMA-MAAsp) nanoparticles were characterized by means of elemental analysis, Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM).Öğe Molecular imprinted polypyrrole modified glassy carbon electrode for the determination of tobramycin(Pergamon-Elsevier Science Ltd, 2013) Gupta, Vinod Kumar; Yola, Mehmet Lutfi; Ozaltin, Nuran; Atar, Necip; Ustundag, Zafer; Uzun, LokmanOver the past two decades, molecular imprinted polymers have attracted a broad interest from scientists in sensor development. In the preparation of molecular imprinted polymers the desired molecule (template) induces the creation of specific recognition sites in the polymer. In this study, the glassy carbon electrode (GCE) based on molecularly imprinted polypyrrole (PPy) was fabricated for the determination of tobramycin (TOB). The developed electrode was prepared by incorporation of a template molecule (TOB) during the electropolymerization of pyrrole on GCE in aqueous solution using cyclic voltammetry (CV) method. The performance of the imprinted and non-imprinted electrodes was evaluated by square wave voltammetry (SWV). The effect of pH, monomer and template concentrations, electropolymerization cycles on the performance of the imprinted and non-imprinted electrodes was investigated and optimized. The non-modified and TOB-imprinted surfaces were characterized by using atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS) and CV. The linearity range of TOB was 5.0 x 10(-10)-1.0 x 10(-8) M with the detection limit of 1.4 x 10(-10) M. The developed nanosensor was applied successfully for the determination of TOB in egg and milk. (C) 2013 Elsevier Ltd. All rights reserved.Öğe Molecularly imprinted cryogel cartridges for the specific filtration and rapid separation of interferon alpha(Royal Soc Chemistry, 2015) Corman, Mehmet Emin; Armutcu, Canan; Ozkara, Serpil; Uzun, Lokman; Denizli, AdilIn this study, we synthesised specific filtration cartridges with selective recognition sites for target molecules and used them to separate interferon alpha-2b from aqueous solutions. We combined molecular imprinting technology with cryogel to achieve specific and rapid filtration of interferon alpha-2b through the macroporous structure of a cryogel network. Recombinant interferon alpha-2b-imprinted poly(2-hydroxyethyl methacrylate-N-methacryloyl-L-tryptophan) P(HEMATrp)/alpha-2bIFN cryogels were synthesised via free-radical bulk polymerisation under partially frozen conditions. The interferon alpha-2b filtration conditions were subsequently optimised with respect to factors such as pH, initial concentration, temperature, centrifugation speed, salt concentration and type and the amount of precomplex incorporated. Selectivity experiments were conducted in respect to isoelectric point as well as size of the competitor proteins under both uncompetitive and competitive conditions. The relative selectivity coefficients of the specific filtration cartridge in respect to isoelectronic points for interferon/ IgG, interferon/HSA and interferon/insulin pairs were 3.72, 7.10 and 10.68 times greater than the coefficient of a non-imprinted [P(HEMATrp)] filtration cartridge, respectively. Similarly, the relative selectivity coefficients of the specific filtration cartridge in respect to competitor size for interferon/ lysozyme, interferon/myoglobin and interferon/carbonic anhydrase pairs were calculated as 7.58, 10.40 and 11.68 under uncompetitive conditions whereas those values under competitive conditions were calculated as 1.08, 1.05 and 1.34, respectively. The results indicated that specific filtration cartridges developed could repeatedly adsorb interferon alpha-2b with a short separation time without any significant decrease in the adsorption capacity even if competitive conditions were conducted.Öğe Polisiklik Aromatik Hidrokarbonların Ön-Deriştirilmesi İçin Seçici Monolitik Afinite Kolonların Tasarlanması ve İki-boyutlu HPLC Sistemiyle Tek Aşamada Tayini(2016) Çorman, Mehmet Emin; Uzun, LokmanSunulan projede, Polisiklik aromatik hidrokarbonların (PAH) ön-deristirilmesi için hidrofobik etkilesimlere dayalı etkin ve kolay hazırlanabilir yeni nesil monolitik afinite HPLC kolonlar gelistirilmis ve bu kolonlar ile PAH?ların on-line ön-deristirilmesi ve eser miktarda tayini gerçeklestirilmistir. HPLC ve monolitik kolonların kombinasyonu ile olusturulan yüksek performanslı sıvı afinite kolonlar (HPLAC) istenilen maddenin özütleme ve ön-deristirilmesini saglayarak; eser miktardaki PAH?ların son tayinine yönelik on-line alternatif bir yöntem sunmustur. Çalısmanın ilk asamasında pseudospesifik ligand N-metakriloil-L-fenilalanin (MAPA), L-fenilalanin ve metakriloil klorür kullanılarak sentezlenmistir. Monolitik kolonlar, MAPA monomeri ile 2-hidroksietil metakrilat (HEMA)?ın yıgın polimerizasyonu ile çelik kolonların içinde üretilmistir. Sentezlenen MAPA monomeri, Fourier Transform Infrared Spektroskopisi (FTIR) ve Nükleer Manyetik Rezonans (NMR) ile karakterize edilmistir. Poli(HEMA-MAPA) monolitik kolonlar, FTIR, Taramalı Elektron Mikroskopisi ve elementel analiz ile karakterize edilmistir. Hazırlanan monolitik kolonlar, sulu çözeltilerden Benzo[a]piren (BaP) ön-deristirme islemlerinde kullanılmıs ve ön-deristirme kosulları optimize edilmistir. Optimizasyon çalısmaları kapsamında; BaP derisimi, sıcaklık, enjeksiyon hacmi, akıs hızı tek boyutlu HPLC (1D-HPLC) sisteminde gerçeklestirilmistir. Çalısmanın ikinci asamasında toksisiteleri ve zararlı etkileri dikkate alınarak tehlikeli atık bölgelerde en sık bulunan PAH örnekleri, PAH?ların on-line ön-deristirilmesi ve eser miktarda tayini islemleri için 2-boyutlu HPLC (2D-HPLC) sisteminde analiz edilmistir. Çalısmanın nihai amacı olan, ön-deristirme sonucunda monolitik kolonlar ile daha düsük derisimlere inilerek PAH moleküllerinin 2D-HPLC ile tayini basarılı biçimde gerçeklestirilmistir.Öğe Production of L-Histidine Imprinted Fluorescent Nanoparticles(2nd International Conference on Bio-Sensing Technology, 2011) Çorman, Mehmet Emin; Üzek, Recep; Güngüneş, Hakan; Şenel, Serap; Uzun, Lokman; Say, Rıdvan; Denizli, Adil[Abstract Not Available]Öğe Purification of Fab and Fc using papain immobilized cryogel bioreactor separator system(Elsevier, 2020) Armutcu, Canan; Corman, Mehmet Emin; Bayram, Engin; Uzun, LokmanThe continuous bed bioreactor systems have been used for the production of protein therapeutics, such as IgG, using immobilized enzyme in biopharmaceutical applications. We developed macroporous poly(hydroxyethyl methacrylate-co-glycidyl methacrylate) cryogel-based bioreactor matrix using sodium dodecyl sulfate as surfactans in the presence of ethylene glycol dimethacrylate as cross linking agent by bulk polymerization. The developed polyGMA immobilized bioreactor with papain enzyme was used for specific fragmentation of immunoglobulin G. The catalysis efficiency for immobilized enzyme were investigated in comparison with free enzyme. The immobilized papain displayed broad catalytic activity over a variety of conditions, with maximal activity around pH 7.0 and 70 degrees C. The Michaelis-Menten kinetic constant (K-m), the maximum reaction velocity (V-max), and the catalytic efficiency (k(cat)) for free enzyme were 0.1097 mg/mL, 29.9 mg/mL/min, and 92.01 1/min, respectively, whereas for immobilized enzyme, K-m, V-max, and k(cat) values were 0.1078 mg/mL, 30.53 mg/mL/min, and 94.3 1/min, respectively. In a further step, after digestion, remarkable digestion products of bioreactor, Fab and Fc fragments, produced with immobilized papain bioreactors were analyzed in two ways by SDS-PAGE and reversed-phase HPLC; it was demonstrated that papain immobilized bioreactor successfully used for the digestion of human IgG with high activity. Therefore, the polyGMA cryogel immobilized with papain exhibited a very effective matrix for the bioreactor which can be considered as an alternative bioreactor matrix with great promise in biopharmaceutical applications.Öğe Rapid Analysis of Polycyclic Aromatic Hydrocarbons in Water Samples Using an Automated On-line Two-Dimensional Liquid Chromatography(Springer International Publishing Ag, 2019) Armutcu, Canan; Ozgur, Erdogan; Karasu, Tunca; Bayram, Engin; Uzun, Lokman; Corman, Mehmet EminTwo-dimensional HPLC (2D-HPLC) recently has received great attention due to providing high resolving power and higher peak capacities than that of 1D-HPLC, especially dealing with a wide spectrum of sample matrices containing several components. In this work, an on-line heart-cutting two-dimensional liquid chromatography (2D-LC) method was developed using monolithic columns coupled with reversed-phase liquid chromatography (RPLC). 2D-HPLC was successfully carried out using affinity-based monolithic columns at first dimension (20 cm x 4.6 mm I.D.) followed by a Pinnacle II PAH column (50 mm x 4.6 mm I.D.) at the second dimension. Furthermore, good linearity was observed for the correlation of the benzo[a]pyrene (BaP) molecule against the peak areas (R-2 = 0.994) in the concentration range of 0.01-1.0 ng/mL in 30 min. The limit of detection and the limit of quantification were found to be 4.0 pg/mL and 12.0 pg/mL, respectively. Both the intra-day and inter-day precision at 0.01 and 0.1 ng/mL spiked concentrations were below than 2.35% RSD whereas the means of the recovery data of the BaP from the water samples were found to be in the range of 93.71-98.65%. These results demonstrate that the 2D-HPLC system, developed by the combination of the P(HEMA-MAPA) column and Pinnacle II PAH column, is reliable, stable, and well qualified in the extraction of polycyclic aromatic hydrocarbons from the water samples.Öğe Rapid, efficient and selective preconcentration of benzo[a]pyrene (BaP) by molecularly imprinted composite cartridge and HPLC(Elsevier, 2017) Corman, Mehmet Emin; Armutcu, Canan; Uzun, Lokman; Denizli, AdilIn this study, cryogel-based molecularly imprinted composite cartridges were designed for the rapid, efficient, and selective preconcentration of benzo[a]pyrene (BaP) from water samples. First, a BaP-imprinted poly(2-hydroxyethyl methacrylate-N-methacryloyl-(L)-phenylalanine) composite cartridge was synthesized under semi-frozen conditions and characterized by scanning electron microscopy, elemental analysis, Fourier transform infrared spectroscopy, and swelling tests. After the optimization of preconcentration parameters, i.e., pH and initial BaP concentration, the selectivity and preconcentration efficiency, and reusability of these cartridges were also evaluated. In selectivity experiments, BaP imprinted composite cartridge exhibited binding capacities 3.09, 9.52, 8.87, and 8.77-fold higher than that of the non-imprinted composite cartridge in the presence of competitors, such as benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), indeno[1,2,3-cd]pyrene (lcdP), and 1-naphthol, respectively. The method detection limit (MDL), relative standard deviation (RSD) and preconcentration efficiency (PE) of the synthesized composite cartridge were calculated as 24.86 mu g/L, 1.60%, and 349,6%, respectively. (C) 2016 Elsevier B.V. All rights reserved.Öğe Reversible and easy post-crosslinking method for developing a surface ion-imprinted hypercrosslinked monolith for specific Cd(II) ion removal from aqueous solutions(Royal Soc Chemistry, 2016) Corman, Mehmet Emin; Armutcu, Canan; Uzun, Lokman; Say, Ridvan; Denizli, AdilIn this study, a new surface imprinting technique for preparing a hypercrosslinked monolith to remove Cd(II) ions out from aqueous solutions was proposed. The monoliths were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermal gravimetrical analysis, surface area measurements and elemental analysis. The reversible nature of the hypercrosslinking process was proved by repeated crosslinking and denaturation cycles by using ferric ions as an oxidant and urea as a reductant, respectively meanwhile performing surface area measurements for both situations to demonstrate the variation in the surface porosity. The multipoint BET surface areas of poly(HEMA), surface ion imprinted (Cd-SII-HM) and non-imprinted (NI-HM) monoliths were determined as 269.1 m(2) g(-1), 79.1 m(2) g(-1), and 67.4 m(2) g(-1), respectively. By breaking hypercrosslinks, the micropore volume decreased from 39.7 mm3 g-1 to 11.8 mm(3) g(-1) while the cumulative pore volume decreased from 30.7 mm(3) g(-1) to 9.1 mm(3) g(-1) during urea treatment. At the first step, the affecting factors such as initial Cd(II) ion concentrations, pH and adsorption time were optimized. Then, the selectivity of the Cd-SII-HM for Cd(II) against other metal ions was evaluated not only from singular solutions but also from triple and quadruple solutions, which included Pb(II), Zn(II) and Hg(II) ions as competitors. The relative selectivity coefficients were calculated as 3.28, 15.61 and 58.55 for Cd(II)/Zn(II), Cd(II)/Pb(II) and Cd(II)/Hg(II) pairs. The results obtained indicated that the developed reversible and easy post-crosslinking method is quite applicable for producing the surface ion-imprinted polymers with high selectivity for the template ions [Cd(II)] regarding the potential competitor ions [Zn(II), Pb(II) and Hg(II)].Öğe Self-oriented nanoparticles for site-selective immunoglobulin G recognition via epitope imprinting approach(Elsevier, 2014) Corman, Mehmet Emin; Armutcu, Canan; Uzun, Lokman; Say, Ridvan; Denizli, AdilMolecular imprinting is a polymerization technique that provides synthetic analogs for template molecules. Molecularly imprinted polymers (MIPs) have gained much attention due to their unique properties such as selectivity and specificity for target molecules. In this study, we focused on the development of polymeric materials with molecular recognition ability, so molecular imprinting was combined with miniemulsion polymerization to synthesize self-orienting nanoparticles through the use of an epitope imprinting approach. Thus, L-lysine imprinted nanoparticles (LMIP) were synthesized via miniemulsion polymerization technique. Immunoglobulin G (IgG) was then bound to the cavities that specifically formed for L-lysine molecules that are typically found at the C-terminus of the Fc region of antibody molecules. The resulting nanoparticles makes it possible to minimize the nonspecific interaction between monomer and template molecules. In addition, the orientation of the entire IgG molecule was controlled, and random imprinting of the IgG was prevented. The optimum conditions were determined for IgG recognition using the imprinted nanoparticles. The selectivity of the nanoparticles against IgG molecules was also evaluated using albumin and hemoglobin as competitor molecules. In order to show the self-orientation capability of imprinted nanoparticles, human serum albumin (HSA) adsorption onto both the plain nanoparticles and immobilized nanoparticles by anti-human serum albumin antibody (anti-HSA antibody) was also carried out. Due to anti-HSA antibody immobilization on the imprinted nanoparticles, the adsorption capability of nanoparticles against HSA molecules vigorously enhanced. It is proved that the oriented immobilization of antibodies was appropriately succeeded. (C) 2014 Elsevier B.V. All rights reserved.Öğe Synthesis and characterization of stimuli-responsive hydrogels: evaluation of external stimuli influence on L929 fibroblast viability(Iop Publishing Ltd, 2022) Karasu, Tunca; Erkoc-Biradli, Fatma Zehra; Ozturk-Oncel, M. Ozgen; Armutcu, Canan; Uzun, Lokman; Garipcan, Bora; Corman, Mehmet EminIn this study, poly(2-hydroxyethylmethacrylate) [p(HEMA)] based hydrogels responsive to the pH, temperature and magnetic field were synthesized. The surface properties of p(HEMA) were improved by designing the stimuli-responsive hydrogels made of MAGA, NIPAAm and methacrylate-decorated magnetite nanoparticles as a function of pH-, thermo- and magnetic responsive cell culture surfaces. These materials were then modified an abundant extracellular matrix component, type I collagen, which has been considered as a biorecognition element to increase the applicability of hydrogels to cell viability. Based on results from scanning electronmicroscopy (SEM) and thermal gravimetric analysis (TGA), stimuli-responsive hydrogel demonstrated improved non-porous structures and thermal stability with a high degree of cross-linking. Mechanical analyses of the hydrogels also showed that stimuli-responsive hydrogels are more elastomeric due to the polymeric chains and heterogeneous amorphous segments compared to plain hydrogels. Furthermore, surface modification of hydrogels with collagen provided better biocompatibility, which was confirmed with L929 fibroblast cell adhesion. Produced stimuli-responsive hydrogels modulated cellular viability by changing pH and magnetic field.
