Yazar "Ocsoy, Ismail" seçeneğine göre listele

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    Horseradish peroxidase-based hybrid nanoflowers with enhanced catalytical activities for polymerization reactions of phenol derivatives
    (Wiley, 2020) Gokturk, Ersen; Ocsoy, Ismail; Turac, Ersen; Sahmetlioglu, Ertugrul
    Catalytic activity and stability of HRP-Cu2+ hybrid nanoflowers (hCu-NFs) in the polymerization reactions of phenol derivatives was investigated. It was observed that the catalytic activity and stability of hybrid nanoflowers on the polymerization of the phenol derivatives was considerably higher compared to free Horseradish peroxidase (HRP) enzyme. The hCu-NFs effectively polymerized phenolic compounds as a novel nanobiocatalyst and led to polymers having quite high yields, molecular weights, and thermal stabilities compared to free HRP enzyme. The hCu-NFs provide substantial repeated use and showed some degree of catalytic activity even after fourth cycle experiment in the polymerization reactions.
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    Investigation of Peroxidase-Like Activity of Flower-Shaped Nanobiocatalyst from Viburnum Opulus L. Extract on the Polymerization Reactions
    (2024) Kalaycı, Berkant; Kaplan, Naime; Mirioğlu, Müge; Dadı, Şeyma; Ocsoy, Ismail; Göktürk, Ersen
    Here, we report the effects of peroxidase-mimicking activity of flower shaped hybrid nanobiocatalyst obtained from Viburnum-Opulus L. (Gilaburu) extract and Cu2+ ions on the polymerization of phenol and its derivatives (guaiacol and salicylic acid). The obtained nanoflowers exhibited quite high catalytic activity upon the polymerization of phenol and guaiacol. The yields and the number average molecular weights of the obtained polymers were significantly high. Due to solubility issue of salicylic acid in aqueous media, polymerization of salicylic acid resulted in very low yields. Free-horseradish peroxidase (HRP) enzyme is known to be losing its catalytic activity at 60 °C and above temperatures. However, the synthesized nanoflowers exhibited quite high catalytic activity even at 60 °C and above reaction temperatures. This provides notable benefits for reactions needed at high temperatures, and it is very important to use these kinds of nanobiocatalysts for both scientific studies and industrial applications.
  • Küçük Resim
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    Investigation of Peroxidase-Like Activity of Flower-Shaped Nanobiocatalyst from Viburnum Opulus L. Extract on the Polymerization Reactions
    (Turkish Chemical Society, 2024) Kalayci, Berkant; Kaplan, Naime; Mirioglu, Muge; Dadi, Seyma; Ocsoy, Ismail; Gokturk, Ersen
    Here, we report the effects of peroxidase-mimicking activity of flower shaped hybrid nanobiocatalyst obtained from Viburnum-Opulus L. (Gilaburu) extract and Cu2+ ions on the polymerization of phenol and its derivatives (guaiacol and salicylic acid). The obtained nanoflowers exhibited quite high catalytic activity upon the polymerization of phenol and guaiacol. The yields and the number average molecular weights of the obtained polymers were significantly high. Due to solubility issue of salicylic acid in aqueous media, polymerization of salicylic acid resulted in very low yields. Free-horseradish peroxidase (HRP) enzyme is known to be losing its catalytic activity at 60 °C and above temperatures. However, the synthesized nanoflowers exhibited quite high catalytic activity even at 60 °C and above reaction temperatures. This provides notable benefits for reactions needed at high temperatures, and it is very important to use these kinds of nanobiocatalysts for both scientific studies and industrial applications. © 2024, Turkish Chemical Society. All rights reserved.
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    Production of flower-shaped nanobiocatalysts from green tea and investigation of their peroxidase mimicking activity on the polymerization of phenol derivatives
    (Wiley, 2024) Kalayci, Berkant; Kaplan, Naime; Dadi, Seyma; Ocsoy, Ismail; Gokturk, Ersen
    Enzyme catalyzed reactions are known to be environmental friendly and easy method for many applications. However, utilization of enzymes in a variety of reactions is strictly limited due to their high cost, instability in aqueous solutions, denaturation in organic solvents and high temperatures. For this reason, it is important to discover new generation catalyst systems indicating enzyme-like catalytic activity. Here, we report hybrid organic-inorganic flower-shaped green tea-Cu2+ nanobiocatalyst synthesized from green tea extract as an organic component and copper (II) ions (Cu2+) as inorganic component. The effect of the peroxidase-mimicking activity of green tea-Cu2+ nanobiocatalyst was investigated on the polymerization of phenol and derivatives (guaiacol and salicylic acid) through Fenton-like reaction mechanism. Obtained successful outcomes showed that the synthesized nanobiocatalyst showed very high catalytic activity upon polymerization of phenol and guaiacol. The slight solubility of salicylic acid in water limited to achieve its polymerization under-performed reaction conditions. The yields and molecular weights of the obtained polymers were found to be quite high. While free peroxidase enzymes like horseradish peroxidase (HRP) enzyme loses its catalytic activity at 60 degrees C and above temperatures, green tea-Cu2+ nanobiocatalyst exhibited very high catalytic activity upon polymerization reactions even at 60 degrees C reaction temperature. This outcome provides significant advantages in some reactions requiring high temperatures. In order to understand the origin of the catalytic activity of the green tea-Cu2+ nanoflowers, similar biocatalysts were also synthesized from caffeine and catechin alkaloids which are the active components of green tea. Caffeine-Cu2+ and catechine-Cu2+ nanobiocatalysts also exhibited quite high catalytic activity toward polymerization of phenol and derivatives. We suggest that green tea-Cu2+ and similar types of nanobiocatalysts may expand their utilization in polymer chemistry as promising catalytic agents for radicalic polymerizations.
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    Synthesis of metallic and metal oxide nanomaterials
    (Wiley Blackwell, 2020) Demirbas, Ayse; Karaytuğ, Tuna; Arabaci, Nihan; Yilmaz, Ebru Sebnem; Ocsoy, Ismail
    Materials in nano size called "nanomaterials" convey novel and enhanced properties based upon their size, shape, morphology, and component and have been intensively employed in a variety of scientific and industrial fields. Specifically, nanomaterials have been exposed to humans, plants, and animals, so toxicity of nanomaterials is a crucial issue that must be investigated and documented when exposed to living organisms. Researchers have focused on various surfactants, surface engineering strategies, and synthesis methods to create less harmful or biocompatible nanomaterials. This present review comprehensively and comparatively focuses on most rapid growth and exciting research on a variety of nanomaterials, their synthesis methods, and nanomaterial surface designing strategies. © 2021 John Wiley & Sons Ltd.