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Article Citation - WoS: 11Citation - Scopus: 12Ag Nanostructures on a Poly(3,4-Ethylenedioxythiophene) Film Prepared With Electrochemical Route: a Controllable Roughened Sers Substrate With High Repeatability and Stability(Pergamon-elsevier Science Ltd, 2012) Dogan, Uzeyir; Kaya, Murat; Cihaner, Atilla; Volkan, MurvetA simple, reliable and reproducible one-step electrochemical method for the preparation of surface-enhanced Raman-active polymer-mediated silver nanoparticles (Ag NPs) on planar indium tin oxide (ITO) coated glass substrates was reported. Poly(3,4-ethylenedioxythiophene) (PEDOT) film was used as a support material for dispersing nanostructured silver nanostructures on the surface homogeneously, since 3,4-ethylenedioxythiophene (EDOT) monomer polymerizes regioregularly. The optical properties and morphologies of the silver substrates have been investigated by ultraviolet-visible (UV-vis) spectroscopy and field emission scanning electron microscopy (FE-SEM). The UV-vis and FE-SEM results revealed that the Ag nanostructures separately appeared on the PEDOT coated ITO after reduction. The effect of the thickness of PEDOT polymer film, reduction potential of silver, the concentration of silver ion solution and the amount of silver particle on the polymer film on the SERS response were studied as well as repeatability and temporal stability of prepared substrates. Brilliant cresyl blue (BCB) has been used as Raman probes to evaluate the properties of the new SERS substrates. Signals collected over multiple spots within the same substrate resulted in a relative standard deviation (RSD) of 9.34%, while an RSD of 11.05% was measured in signals collected from different substrates. The SERS-active substrates were robust and stable which lost only 5.71% of initial intensity after 1 month. (C) 2012 Elsevier Ltd. All rights reserved.Article Citation - WoS: 35Citation - Scopus: 32Preparation of Silica Coated Cobalt Ferrite Magnetic Nanoparticles for the Purification of Histidine-Tagged Proteins(Pergamon-elsevier Science Ltd, 2015) Aygar, Gulfem; Kaya, Murat; Ozkan, Necati; Kocabiyik, Semra; Volkan, MurvetSurface modified cobalt ferrite (CoFe2O4) nanoparticles containing Ni-NTA affinity group were synthesized and used for the separation of histidine tag proteins from the complex matrices through the use of imidazole side chains of histidine molecules. Firstly, CoFe2O4 nanoparticles with a narrow size distribution were prepared in an aqueous solution using the controlled co-precipitation method. In order to obtain small CoFe2O4 agglomerates, oleic acid and sodium chloride were used as dispersants. The CoFe2O4 particles were coated with silica and subsequently the surface of these silica coated particles (SiO2-CoFe2O4) was modified by amine (NH2) groups in order to add further functional groups on the silica shell. Then, carboxyl (-COOH) functional groups were added to the SiO2-CoFe2O4 magnetic nanoparticles through the NH2 groups. After that N alpha,N alpha-Bis(carboxymethyl)-L-lysine hydrate (NTA) was attached to carboxyl ends of the structure. Finally, the surface modified nanoparticles were labeled with nickel (Ni) (II) ions. Furthermore, the modified SiO2-CoFe2O4 magnetic nanoparticles were utilized as a new system that allows purification of the N-terminal His-tagged recombinant small heat shock protein, Tpv-sHSP 14.3. (C) 2015 Elsevier Ltd. All rights reserved.

