Browsing by Author "Uygun, DA"

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    Metal-chelated cryogels for amyloglucosidase adsorption: application for continuous starch hydrolysis
    Evli, S; Orhan, H; Aktas, PS; Uygun, M; Uygun, DA
    In the present work, a new metal-chelating platform was designed by using IDA as a chelating agent and Cu(II) as an affinity component for amyloglucosidase adsorption. Poly(AAm-GMA) cryogels were used as structural elements, while GMA monomer served reactive epoxy groups for IDA immobilization. Synthesized cryogels were characterized by FTIR, SEM and EDX studies. Pore diameter of the whole polymeric structure was 3-10 Effects of medium pH, temperature, ionic strength along with amyloglucosidase concentration were also investigated for more effective amyloglucosidase adsorption and maximum adsorbed amount of amyloglucosidase was cryogel by the optimum conditions. Reusability profile of the poly(AAm-GMA)-IDA-cryogels was also studied and it was found that the synthesized cryogels could be used repeatedly for many times without any significant decrease on their adsorption capacity. Also continuous hydrolysis of starch by using immobilized form of amyloglucosidase in a column system was studied.
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    Hydrophobic nano-carrier for lysozyme adsorption
    Altunbas, C; Ural, FZ; Uygun, M; Avcibasi, N; Avcibasi, U; Uygun, DA; Akgöl, S
    In this work, poly(HEMA-APH) nanoparticles were synthesized by surfactant-free emulsion polymerization technique. Magnetic behaviour was introduced by simple addition of Fe3O4 into the polymerization medium. Characterization of the nanoparticle was carried out by FTIR, ESR, SEM, AFM and EDX analyses. These synthesized magnetic nanoparticles were used for adsorption of lysozyme. For this purpose, adsorption conditions were optimized and maximum lysozyme binding capacity was found to be 278.8 mg g(-1) polymer in pH 7.0 phosphate buffer at 25(a similar to)C. Desorption and reusability properties of the nanoparticles were investigated and lysozyme adsorption efficiency did not change significantly at the end of the 10 successive reuses.
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    Synthesis and biodistribution of novel magnetic-poly(HEMA-APH) nanopolymer radiolabeled with iodine-131 and investigation its fate in vivo for cancer therapy
    Avcibasi, U; Avcibasi, N; Akalin, HA; Ediz, M; Demiroglu, H; Gümüser, FG; Özçaliskan, E; Türkcan, C; Uygun, DA; Akgöl, S
    Herein, we investigated the biological uptake, distribution, and radiopharmaceutical potential of a novel molecule based on 2-hydroxyethyl methacrylate (HEMA) and anilinephtalein (APH) in the metabolism of Albino Wistar rats. In order to achieve this, we synthesized APH using organic synthesis methods and copolymerized APH with HEMA using a common polymerization method, surfactant-free emulsion polymerization. In the presence of Fe3O4 particles, we obtained a new generation magnetic-nano-scale polymer, magnetic-poly(HEMA-APH). This new molecule was chemically identified and approved by several characterization methods using Fourier transform infrared spectroscopy, scanning electron microscope, energy dispersive X-ray spectroscopy, electron spin resonance, atomic force microscope, and Zeta particle-size analysis. To evaluate the biological activity in live metabolism and anti-cancer potential of mag-poly(HEMA-APH), molecule was radioiodinated by a widely used labeling technique, iodogen method, with a gamma diffuser radionuclide, I-131. Thin-layer radiochromatography experiments demonstrated that I-131 binded to nanopolymer with the labeling yield of 90 %. Lipophilicity and stability experiments were conducted to determine the condition of cold and labeled mag-poly(HEMA-APH) in rat blood and lipid medium. Results demonstrated that radioiodinated molecule stayed as an intact complex in rat metabolism for 24 h and experimental lipophilicity was determined as 0.12 +/- A 0.02. In vivo results obtained by imaging and biological distribution experiments indicated that mag-poly(HEMA-APH) labeled with I-131 [I-131-mag-poly(HEMA-APH)] highly incorporated into tissues of the uterus, the ovarian, the prostate, and the lungs in rat metabolism. Based on these results, it may be evaluated that novel mag-poly(HEMA-APH) molecule labeled with I-131 is a compound which has a significant potential for being used as an anti-cancer agent. Certain results can only be obtained whether this molecule is applied to adenocarcinoma cell models and tumor-bearing animals.
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    Immobilization of amyloglucosidase onto macroporous cryogels for continuous glucose production from starch
    Uygun, M; Akduman, B; Ergönül, B; Uygun, DA; Akgöl, S; Denizli, A
    Poly(methyl methacrylate-glycidyl methacrylate) [Poly(MMA-GMA)] cryogels were synthesized using monomers of methylmethacrylic acid and epoxy group bearing GMA via radical cryopolymerization technique. Synthesized cryogels were used for the immobilization of amyloglucosidase to the cryogel surface using epoxy chemistry. Characterizations of the free and immobilized amyloglucosidase were carried out by comparing the optimum and kinetic parameters of enzymes. For this, pH and temperature profiles of free and immobilized preparation were studied and, it was found that, optimum pH of enzyme was not change upon immobilization (pH 5.0), while optimum temperature of the enzyme shifted 10 degrees C to warmer region after immobilization (optimum temperatures for free and immobilized enzyme were 55 and 65 degrees C, respectively). Kinetic parameters of free and immobilized enzyme were also investigated and K-m values of free and immobilized amyloglucosidase were found to be 2.743 and 0.865mg/mL, respectively. V-max of immobilized amyloglucosidase was found to be (0.496 mu mol/min) about four times less than that of free enzyme (2.020 mu mol/min). Storage and operational stabilities of immobilized amyloglucosidase were also studied and it was showed that immobilized preparation had much more stability than free preparation. In the present work, amyloglucosidase immobilized poly(MMA-GMA) cryogels were used for continuous glucose syrup production from starch for the first time. Efficiency of immobilized enzyme was investigated and released amount of glucose was found to be 2.54mg/mL at the end of the 5min of hydrolysis. The results indicate that the epoxy functionalized cryogels offer a good alternative for amyloglucosidase immobilization applications with increased operational and thermal stability, and reusability. Also, these cryogels can be used for immobilization of other industrially valuable enzymes beyond amyloglucosidase.