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    Synthesis of Long-Term Stable Gold Nanoparticles Benefiting from Red Raspberry (Rubus idaeus), Strawberry (Fragaria ananassa), and Blackberry (Rubus fruticosus) Extracts-Gold Ion Complexation and Investigation of Reaction Conditions
    (Amer Chemical Soc, 2019) Demirbas, Ayse; Buyukbezirci, Kasim; Celik, Cagla; Kislakci, Emine; Karaagac, Zehra; Gokturk, Ersen; Kati, Ahmet
    We report synthesis of monodispersed, stable, and colloidal gold nanoparticles (Au NPs) using anthocyanin-riched red raspberry (Rubus idaeus), strawberry (Fragaria ananassa), and blackberry (Rubus fruticosus) extracts as functions of concentration of HAuCl4 center dot 3H(2)O and berries extract, reaction time, and reaction pH values (pHs) and demonstrate their unique stability in highly concentrated salt (sodium chloride, NaCl) solutions. The catecholamine group of anthocyanin molecules give preferential coordination reaction with gold ions (Au3+) for creating anthocyanin-Au3+ complexes, which may lead to initiation of nucleation for seed formation, and then, oxidation of catecholamine results in a flow of electrons from anthocyanins to Au seeds for anisotropic growth. Finally, the surface of the Au NPs is saturated with anthocyanins, and formation of monodispersed and stable Au NPs with narrow size distribution is completed. We also report the effects of some experimental parameters including concentrations of Au3+ ions and barrier extracts, reaction time, and pHs on formation of the Au NPs with rational explanations. The long-term colloidal stability of the Au NPs in the 400 mM NaCl solution was comparatively studied with commercial Au NPs (citrate capped). As results show that anthocyanin-riched berry extracts directed Au NPs we proposed here can be considered as promising and safe tools for biomedical applications owing to their highly much colloidal dispersibility and salt tolerance properties.
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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.