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    Adsorption of Victoria Blue R (VBR) dye on magnetic microparticles containing Fe(II)–Co(II) double salt
    (Taylor and Francis Inc., 2016) Erol, Kadir; Köse, Kazım; Köse, Dursun Ali; Sızır, Ümit; Tosun Satır, İlknur; Uzun, Lokman
    Magnetic microparticles have many applications in various areas today. The aim of this study was to develop hydrophobic magnetic microparticles as an alternative to traditional methods for high capacity and low cost removal of Victoria Blue R (VBR), which is valuable for industry and commercial, from wastewater and to determine the VBR adsorption ability of this adsorbent. Fe(II)–Co(II) double salt incorporated magnetic poly(2-hydroxyethyl methacrylate-N-methacryloyl-l-tryptophan) [m-poly(HEMA-MATrp)] microparticles were synthesized and used as adsorbent. These microparticles were synthesized in aqueous dispersion medium via microemulsion polymerization using MATrp and HEMA monomers. Magnetic hydrophobic microparticles were characterized via Fourier transform infrared spectroscopy, scanning electron microscopy, and vibrating sample magnetometer. Adsorption experiments were conducted for different conditions (pH, interaction time, amount of microparticles, temperature, and ionic strength) in batch system. VBR adsorption capacity of magnetic hydrophobic microparticles was estimated as 89.46 ?mol/g. Adsorption–desorption cycles were repeated 4 times, and there was no significant decrease for the adsorption capacity observed. © 2015 Balaban Desalination Publications. All rights reserved.
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    Affinity purification lipase from wheat germ: comparison of hydrophobic and metal chelation effect
    (Taylor and Francis Ltd., 2017) Köse, Kazım; Erol, Kadir; Köse, Dursun Ali; Evci, Emre; Uzun, Lokman
    Cryogels are used quite a lot nowadays for adsorption studies as synthetic adsorbents. In this study, lipase enzyme (obtained from Candida cylindracea) adsorption capacity of poly(2-hydroxyethyl methacrylate-N-methacryloyl-L-tryptophan), poly(HEMA-MATrp), and Cu(II) ions immobilized poly(HEMA-MATrp), poly(HEMA-MATrp)-Cu(II), cryogel membranes were synthesized to determine and compare the adsorption behavior of lipase enzyme. In this regard, the effect of pH, interaction time, lipase initial concentration, temperature and ionic strength on the adsorption capacity of these membranes was investigated. Maximum lipase enzyme adsorption capacities of poly(HEMA-MATrp) and poly(HEMA-MATrp)-Cu(II) cryogel membranes were determined as 166.4 mg/g and 196.4 mg/g, respectively. © 2016 Informa UK Limited, trading as Taylor & Francis Group.
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    Cholesterol removal via cyclodextrin-decoration on cellulose nanocrystal (CNC)-grafted poly(HEMA-GMA) nanocomposite adsorbent
    (Springer, 2021) Kose, Kazim; Mavlan, Miran; Uzun, Lokman; Youngblood, Jeffry P.
    Glycidyl methacrylate (GMA) was grafted to cellulose nanocrystals (CNCs) using hydroquinone resulting in a crosslinkable nanoparticle. 2-Hydroxyethyl methacrylate (HEMA) was used to polymerize this nanoparticle to obtain a polymeric structure with a bridging CNC structure to which cyclodextrin (CD) was attached in order to better capture hydrophobic biomolecules. X-Ray Microscopy and nuclear magnetic resonance methods provided the main characterization data proving the successful modification process. This CD-modified nanocomposite adsorbent was used for the removal of cholesterol and low-density lipoprotein for the first time. Adsorption performance in a continuous system was similar to 99% for both cholesterol and low-density lipoprotein with agreement between experimental data and mathematical models performed. Overall, results indicate that cyclodextrin modified poly(HEMA-GMA-g-CNC) is a promising material for use as an adsorbent for biological and biomedical applications.
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    Fe(II)-Co(II) double salt incorporated magnetic hydrophobic microparticles for invertase adsorption
    (Humana Press Inc., 2015) Köse, Kazım; Erol, Kadir; Emniyet Sert, Asiye Aslı; Köse, Dursun Ali; Alp Avcı, Gülçin; Uzun, Lokman
    Invertase (?-fructofuranoside fructohydrolase, EC 3.2.1.26) is an enzyme widely used in the food industry. Its main function is the formation of glucose and fructose through hydrolysis of sucrose. For the separation and purification of this commercially important enzyme from aqueous solutions, magnetic poly(2-hydroxyethyl methacrylate-N-methacryloyl-L-tryptophan), m-poly(HEMA-MATrp) microparticles were developed. Magnetic properties of microparticles are provided using ferromagnetic Fe(II)-Co(II) double salt. Characterization studies of magnetic microparticles were conducted via vibrating sample magnetometer (VSM), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) analysis. Specific surface area of magnetic microparticles is 6.75 m(2)/g. Because of all experiments performed in this study, the adsorption capability of magnetic microparticles was optimized by variation of different conditions (pH, interaction time, initial invertase concentration, temperature, and ionic strength) and maximum adsorption capacity was determined as 992.64 mg invertase/g magnetic microparticles.
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    Magnetic diatomite for pesticide removal from aqueous solution via hydrophobic interactions
    (Springer Heidelberg, 2019) Erol, Kadir; Yildiz, Emrecan; Alacabey, Ihsan; Karabork, Muharrem; Uzun, Lokman
    Pesticides are highly hazardous chemicals for the environment and human health and their use in agriculture is constantly increasing. Although 1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane 4,4'-DDT was banned at developed countries, it is still one of the most dangerous of chemical due to accumulation in the environment. It is known that the toxicity of DDT affects some enzyme systems biochemically. The main motivation of this study is to develop an effective adsorbate for the removal DDT, which was chosen as a model hydrophobic pesticide, out of aqueous systems. For this purpose, the bare diatomite particles were magnetically modified and a hydrophobic ligand attached to enhance its adsorptive and physio-chemical features. Under optimal conditions, a high adsorption capacity, around 120 mg/g with the hydrophobic and magnetic diatomite particles, modification of the diatomite particles reduced average pores diameter whereas surface area and total pore volume increased (around 15-folds). After five consecutive adsorption-desorption cycles, no significant decrease in adsorption capability was observed. The adsorption isotherms (Langmuir, Freundlich, and Flory-Huggins) applied to the data indicated that the adsorption process occurred via monolayer adsorption in an entropy-driven manner. The kinetic data also revealed the quick adsorption process without any diffusion limitations.
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    Magnetic nanoparticles for plasmid DNA purification through hydrophobic interaction chromatography
    (Taylor and Francis Inc., 2014) Üzek, Recep; Özkara, Serpil; Güngüneş, Hakan; Uzun, Lokman; Şenel, Serap
    Magnetic poly(2-hydroxyethyl methacrylate-co-N-methacryloyl–L-phenyl alanine), p(HEMA-co-MAPA) nanoparticles were produced by emulsion polymerization technique. The nanoparticles were characterized by zetasizer, atomic force microscopy (AFM), transmission electron microscopy (TEM), electron spin resonance spectroscopy (ESR), and Fourier transformed infrared spectroscopy (FTIR) techniques. Experimental conditions were optimized for DNA adsorption in aqueous media. The effects of several factors (i.e., temperature, pH, equilibrium concentration of DNA, salt type, and ionic strength) on adsorption capacity were examined in batch studies. The maximum DNA adsorption capacity was 211.3 mg/g for nanoparticles consisting of magnetite. The adsorption isotherms and kinetics were also examined. The Langmuir model and pseudo second-order kinetics are the best fitted to the data. Following the ten adsorption-desorption cycles, the decrease in adsorption capacity was only 12%. Finally, plasmid DNA was purified from E.coli lysate by magnetite nanoparticles consisting of MAPA. The purity and molecular mass of purified plasmid DNA were determined by the use of agarose gel electrophoresis resulting in 7000 base pairs for molecular mass and OC pDNA form following elution.
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    Modification of cyclodextrin and use in environmental applications
    (Springer Heidelberg, 2021) Kose, Kazim; Tuysuz, Mirac; Aksut, Davut; Uzun, Lokman
    Water pollution, which has become a global problem in parallel with environmental pollution, is a problem that needs to be solved urgently, considering the gradual depletion of water resources. The inadequacy of the water treatment methods and the materials used somehow directed the researchers to look for dual character structures such as biocompatible and biodegradable beta-cyclodextrin (beta-CD). beta-CD, which is normally insoluble in water, is used in demanding wastewater applications by being modified with the help of different agents to be water soluble or transformed into polymeric adsorbents as a result of co-polymerization via cross-linkers. In this way, in addition to the host-guest interactions offered by beta-CD, secondary forces arising from these interactions provide advantages in terms of regeneration and reusability. However, the adsorption efficiency and synthesis steps need to be improved. Based on the current studies presented in this review, in which cross-linkers and modification methods are also mentioned, suggestions for novel synthesis methods of new-generation beta-CD-based materials, criticisms, and recent methods of removal of micropollutants such as heavy metals, industrial dyes, harmful biomolecules, and pharmaceutics wastes are mentioned.
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    Molecularly imprinted polymers in toxicology: a literature survey for the last 5 years
    (Springer Heidelberg, 2021) Kose, Kazim; Kehribar, Demet Yalcin; Uzun, Lokman
    The science of toxicology dates back almost to the beginning of human history. Toxic chemicals, which are encountered in different forms, are always among the chemicals that should be investigated in criminal field, environmental application, pharmaceutic, and even industry, where many researches have been carried out studies for years. Almost all of not only drugs but also industrial dyes have toxic side and direct effects. Environmental micropollutants accumulate in the tissues of all living things, especially plants, and show short- or long-term toxic symptoms. Chemicals in forensic science can be known by detecting the effect they cause to the body with the similar mechanism. It is clear that the best tracking tool among analysis methods is molecularly printed polymer-based analytical setups. Different polymeric combinations of molecularly imprinted polymers allow further study on detection or extraction using chromatographic and spectroscopic instruments. In particular, methods used in forensic medicine can detect trace amounts of poison or biological residues on the scene. Molecularly imprinted polymers are still in their infancy and have many variables that need to be developed. In this review, we summarized how molecular imprinted polymers and toxicology intersect and what has been done about molecular imprinted polymers in toxicology by looking at the studies conducted in the last 5 years.
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    PolyAdenine cryogels for fast and effective RNA purification
    (Elsevier B.V., 2016) Köse, Kazım; Erol, Kadir; Özgür, Erdoğan; Uzun, Lokman; Denizli, Adil
    Cryogels are used effectively for many diverse applications in a variety of fields. The isolation or purification of RNA, one of the potential utilizations for cryogels, is crucial due to their vital roles such as encoding, decoding, transcription and translation, and gene expression. RNA principally exists within every living thing, but their tendency to denaturation easily is still the most challenging issue. Herein, we aimed to develop adenine incorporated polymeric cryogels as an alternative sorbent for cost-friendly and fast RNA purification with high capacity. For this goal, we synthesized the polymerizable derivative of adenine called as adenine methacrylate (AdeM) through the substitution reaction between adenine and methacryloyl chloride. Then, 2-hydroxyethyl methacrylate (HEMA)-based cryogels were prepared in a partially frozen aqueous medium by copolymerization of monomers, AdeM, and HEMA. The cryogels were characterized by using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), surface area measurements, thermogravimetric analysis (TGA), and swelling tests. RNA adsorption experiments were performed via batch system while varying different conditions including pH, initial RNA concentration, temperature, and interaction time. We achieved high RNA adsorption capacity of cryogels, with the swelling ratio around 510%, as 11.86 mg/g. The cryogels might be reused at least five times without significant decrease in adsorption capacity. © 2016 Elsevier B.V.
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    Polyethyleneimine assisted-two-step polymerization to develop surface imprinted cryogels for lysozyme purification
    (Elsevier B.V., 2016) Erol, Kadir; Köse, Kazım; Uzun, Lokman; Say, Rıdvan; Denizli, Adil
    Surface imprinting strategy is one of the promising approaches to synthesize plastic antibodies while overcoming the problems in the protein imprinting research. In this study, we focused our attentions on developing two-step polymerization to imprint on the bare surface employing polyethyleneimine (PEI) assisted-coordination of template molecules, lysozyme. For this aim, we firstly synthesized poly(2-hydroxyethyl methacrylate-glycidyl methacrylate), poly(HEMA-GMA) cryogels as a bare structure. Then, we immobilized PEI onto the cryogels through the addition reaction between GMA and PEI molecules. After that, we determined the amount of free amine (NH2) groups of PEI molecules, subsequently immobilized methacrylate functionalities onto the half of them and another half was used to chelate Cu(II) ions as a mediator between template, lysozyme and PEI groups. After the characterization of the materials developed by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and the micro-computed tomography (?CT), we optimized the lysozyme adsorption conditions from aqueous solution. Before performing lysozyme purification from chicken egg white, we evaluated the effects of pH, interaction time, the initial lysozyme concentration, temperature and ionic strength on the lysozyme adsorption. Moreover, the selectivity of surface imprinted cryogels was examined against cytochrome c and bovine serum albumin (BSA) as the competitors. Finally, the mathematical modeling, which was applied to describe the adsorption process, showed that the experimental data is very well-fitted to the Langmuir adsorption isotherm. © 2016 Elsevier B.V.
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    PolyGuanine methacrylate cryogels for ribonucleic acid purification
    (Wiley-VCH Verlag, 2016) Köse, Kazım; Uzun, Lokman
    The isolation and purification of ribonucleic acid have attracted attention recently for the understanding of the functions in detail because of the necessity for the treatment of genetic diseases. In this study, guanine-incorporated polymeric cryogels were developed to obtain highly purified ribonucleic acid. The satisfactory purification performance was achieved with the guanine-incorporated poly (2-hydroxyethyl methacrylate-guanine methacrylate) cryogels. The most crucial advantages to use guanine as a functional monomer are to obtain a real natural interaction between guanine on the polymeric material and cytosine on the ribonucleic acid. Moreover, using cryogel with a highly porous structure and high swelling ratio provide advantages of getting more water within the structure to get more analyte to interact. The characterization of cryogels has proved the success of the synthesis and the perfect natural interaction to be taken place between the ligand (guanine methacrylate) and the cytosine in the ribonucleic acid molecules. Although the pores within the structure of cryogels are small, they provide efficient and fast adsorption. The chromatographic separation performance was investigated for different conditions (pH, temperature etc.). The desorption ratio and reusability were also analyzed at the end of the five adsorption-desorption cycles with no significant changes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
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    Recent Advancements and New Perspectives of Nanomaterials
    (Springer International Publishing Ag, 2019) Emul, Ezgi; Asik, Mehmet Dogan; Akcan, Ramazan; Kose, Kazim; Uzun, Lokman; Saglam, Semran; Saglam, Necdet
    [Abstract Not Available]
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    Two-step polymerization approach for synthesis of macroporous surface ion-imprinted cryogels
    (Taylor and Francis Inc., 2017) Erol, Kadir; Uzun, Lokman
    Today, the surface imprinted polymers emerge in various fields as synthetic adsorbents gaining attention in a variety of application areas. In this study, Cu(II) ion surface imprinted poly(2-hydroxyethyl methacrylate-glycidyl methacrylate), poly(HEMA-GMA), cryogels were synthesized via modified two-step polymerization which is different from given in literature and the adsorption of Cu(II) ion from aqueous solution was investigated batch wise. In this respect, the method applied in this study is new in the literature despite heavy metal removal studies reported. The polyethyleneimine (PEI) molecule was used in polymeric structure as a ligand. The poly(HEMA-GMA) cryogels prepared was characterized via Fourier transform infrared spectroscopy (FTIR), inductively coupled plasma optical emission spectrometry (ICP-OES), elemental analysis, scanning electron microscopy (SEM) and the micro-computed tomography (?CT). © 2017 Taylor & Francis Group, LLC.