WoS İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/394

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Author: search.filters.author.Dadi, SeymaHas files: No

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  • Article
    Citation - WoS: 1
    Citation - Scopus: 1
    Investigation of the Free-Radical Polymerization of Vinyl Monomers Using Horseradish Peroxidase (HRP) Nanoflowers
    (Springer, 2025-01-24) Ozaydin, Gulbahar; Mirioglu, Muge; Dadi, Seyma; Ocsoy, Ismail; Gokturk, Ersen
    In this study, we report the production of flower-shaped HRP-Cu2+ hybrid nano biocatalyst (HRP-Cu2+ HNF) from the complexation between horseradish peroxidase (HRP) enzyme and Cu2+ ions, and investigate catalytic activity and stability of the obtained nanoflowers on the polymerization of some vinyl monomers (styrene, methylmethacrylate, acrylamide and N-isopropylacrylamide). Polymerizations of these monomers, except water soluble acrylamide, were accomplished under emulsion conditions using cationic, anionic and non-ionic surfactants in the presence of hydrogen peroxide (H2O2) and 2,4-pentanedione mediator. Optimum polymerizations were achieved under the conditions of non-ionic surfactant (tween 40) used. HRP-Cu2+ HNF mediated polymerizations resulted in very high yields and molecular weights (Mn) of the polymers. Optimum polymerization of styrene with 84% of yield (Mn = 319 kDa) was accomplished at room temperature. However, the highest polymerization yields for acrylamide (96%, Mn = 171 kDa) and N-isopropylacrylamide (85%, Mn = 185 kDa) was achieved at 70 degrees C. Similarly, optimum polymerization of methylmethacrylate was accomplished with 84% of yield (Mn = 190 kDa) at 60 degrees C. While free-HRP loses its catalytic activity at 60 degrees C and above temperatures, HRP-Cu2+ HNF showed very high catalytic activity and stability even at 70 degrees C. Increasing activity and stability of hybrid nanoflowers provide significant advantages for both scientific and industrial applications.
  • Article
    Citation - WoS: 2
    Citation - Scopus: 2
    Benefiting From Both Ethanol Oxidation and Bidentate Thiol Groups of DHLA Ligands Under Photoirradiation for Synthesis of Au Nanoparticles With Their Catalytic and Peroxidase Like Activity
    (Amer Chemical Soc, 2025-04-08) Temur, Nimet; Dadi, Seyma; Dogan, Ayse Nur; Nisari, Mustafa; Avan, Ilker; Ocsoy, Ismail
    In this work, we rationally synthesized quite stable gold nanoparticles (AuNPs) using dihydrolipoic acid (DHLA) and DHLA-aspartame (DHLA-Asptm) as both reducing and stabilizing agents in a mixture of water/ethanol at RT under photoirradiation in 10 min. The novelty of this work is that benefiting from both the oxidation of ethanol to ethanal and having the bidentate thiol groups of DHLA, stable DHLA@AuNPs and DHLA-Asptm@AuNPs were successfully and rapidly formed without additional reducing reagents. We systematically examined the formation of DHLA@AuNPs and DHLA-Asptm@AuNPs under different pH values and reaction temperatures. Furthermore, the salt tolerance of DHLA@AuNPs and DHLA-Asptm@AuNPs was tested in a series of sodium chloride solutions. We showed the catalytic and peroxidase-like activities of DHLA@AuNPs against 4-nitrophenol and 3,3 ',5,5 '-tetramethylbenzidine. The AuNPs were characterized by UV-vis spectrophotometry, scanning transmission electron microscopy, zeta potential, and dynamic light scattering.