Yazar "Yilmaz, Betul" seçeneğine göre listele

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    An innovative approach to use zeolite as crosslinker for synthesis of p(HEMA-co-NIPAM) hydrogel
    (Springer Wien, 2022) Durmus, Secil; Yilmaz, Betul; Onder, Alper; Ilgin, Pinar; Ozay, Hava; Özay, Özgür
    This study introduced a modified method to synthesize organic-inorganic hybrid crosslinker based on zeolite. First, zeolite nanoparticles were modified with 3-(aminopropyl)trimethoxysilane. Then, the amine-functionalized zeolite has been reacted with the glycidyl methacrylate via an epoxide ring-opening mechanism. The vinyl-functionalized zeolite was applied as a crosslinking agent to form hydrogel network. A novel temperature-sensitive nanocomposite hydrogel was prepared by crosslinking N-isopropylacrylamide as a comonomer and 2-hydroxyethyl methacrylate as a monomer with free-radical polymerization. Results showed that p(2-hydroxyethyl methacrylate-co-N-isopropylacrylamide)/vinyl-functionalized zeolite nanocomposite hydrogel has a chemically crosslinked and porous network structure. The content of crosslinker and monomers had obvious effects on the swelling ratio of the nanocomposite hydrogel. The temperature and salt-sensitive behavior of the hydrogels are also discussed. We offer a multifunctional crosslinker for preparing sensitive materials that can serve biomedical or environmental applications.
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    Dual use of colorimetric sensor and selective copper removal from aqueous media with novel p(HEMA-co-TACYC) hydrogels: Cyclen derivative as both monomer and crosslinker
    (Elsevier, 2020) Ozay, Hava; Gungor, Zeynep; Yilmaz, Betul; Ilgin, Pinar; Özay, Özgür
    Within the scope of this study, p(2-hydroxyethyl methacrylate-co-tetraacrylic cyclen) (p(HEMA-co-TACYC)) hydrogels were synthesized for the first time in the literature using a tetraacrylic cyclen (TACYC) as both functional monomer and crosslinker. The hydrogels designed especially for Cu2+ ions showed colorimetric sensor behavior selective for Cu2+ ions in all aqueous media (deionized, tap, river and sea water) and in metal ion mixtures. The p(HEMA-co-TACYC) hydrogels forming a stable complex with Cu2+ ions simultaneously showed properties of being a good adsorbent material. The hydrogels have reuse capacity as both sensor and adsorbent material. Changing the amount of TACYC in the hydrogel structure changes the maximum adsorption capacity for Cu2+ ions. The Langmuir and Freundlich adsorption constants for Cu2+ ion adsorption of the hydrogels, acting as selective adsorbent in all aqueous media and metal ion mixtures, were determined.
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    Synthesis of antibiotic-modified silica nanoparticles and their use as a controlled drug release system with antibacterial properties
    (Taylor & Francis Ltd, 2022) Yilmaz, Betul; Özay, Özgür
    In this study, monodispersed silica nanoparticles were synthesized using the Stober method. The synthesized nanoparticles underwent a range of surface modifications and were converted to nanoparticles with drug release and antibacterial features. For modification, firstly -NH2 groups were created on the silica nanoparticle surface using (3-Aminopropyl)triethoxysilane (APTES). In the second stage, hexachlorocyclotriphosphazene (Phz) molecules were bound to the silica nanoparticle surfaces due to these amino groups. In the final stage of modification, the chloride groups in the hexachlorocyclotriphosphazene structure were modified with trimethoprim (TMP) and nanoparticles with antibacterial properties were obtained. The modified silica nanoparticles were characterized with scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR), Transmission Electron Microscopy (TEM), and Thermogravimetric analysis (TGA). The silica-based nanoparticles were used for release of rhodamine 6G, chosen as a model drug. As a result of the drug release studies, the modified silica nanoparticles were found to abide by the Korsmeyer-Peppas low power model and non-Fickian release mechanism as release model. Additionally, nanoparticles both loaded and not loaded with the model drug were determined to have antibacterial properties against Escherichia coli, Bacillus subtilis, and Staphylococcus aureus bacteria.
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    Synthesis, Characterization and Biomedical Applications of p(HEMA-co-APTMACI) Hydrogels Crosslinked with Modified Silica Nanoparticles
    (Biointerface Research Applied Chemistry, 2022) Yilmaz, Betul; Özay, Özgür
    In this study, a new silica-based crosslinker was successfully synthesized with the reaction between silica nanoparticles modified with amino groups and glycidyl methacrylate (GMA). Using the synthesized silica-based crosslinker, p(HEMA) and p(HEMA-co-APTMACI) hydrogels were synthesized for use as drug carrier systems with the free radical polymerization method. The synthesized silica-based crosslinker and hydrogels were characterized using scanning electron microscopy (SEM) and Fourier transform-infrared spectroscopy (FTIR) devices. The swelling behavior of hydrogels cross-linked with silica was investigated in different physiological media. The hydrogels were loaded with sodium diclofenac (NaDc) as a model drug. Drug release studies from the obtained drug-loaded hydrogels were performed at 37 degrees C in PBS (pH 7.0) media. Additionally, the antibacterial properties of the hydrogels synthesized in the study were investigated against E. coli (gram-negative), B. subtilis, and S. aureus (gram-positive) bacteria using the disk diffusion method. At the end of the study, p(HEMA-co-APTMACI) hydrogels were determined to display a better drug release profile than p(HEMA) hydrogels.
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    The preparation of various shapes and porosities of hydroxyethyl starch/p(HEMA-co-NVP) IPN hydrogels as programmable carrier for drug delivery
    (Taylor & Francis Inc, 2020) Özay, Özgür; Ilgin, Pinar; Ozay, Hava; Gungor, Zeynep; Yilmaz, Betul; Kivanc, Mehmet Riza
    This study used biocompatible and biodegradable hydroxyethyl starch (HES), 2-hydroxyethyl methacrylate (HEMA) and N-vinyle-2-pyrrolidone (NVP) monomers for hydrogel synthesis with the aim of use as a drug carrier system. As a result of the synthesis reactions using the redox polymerization technique, hydrogels were produced in both film and cylindrical form. The morphological characterization and structural characterization of hydrogels were performed using scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR), respectively. In addition, swelling characterizations of hydrogels to be used for drug release in various media were examined. The release properties of sodium diclofenac (NaDc) and trimethoprim (TMP) loaded into hydrogels produced in order to use as drug carrier material for controlled drug release were examined in media with pH = 1.2 and 7. It was determined that the hydrogels performed controlled release according to the type of drug and the pH values of the medium. Drug release mechanisms deviated from Fickian mode according to determined drug release rate constants, diffusion exponent (n) and regression values at different pH values. In addition, antibacterial properties of drug-loaded hydrogels against B. subtilus, S. aureus and E. coli were investigated.