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    CTAB modified dellite: A novel support for enzyme immobilization in bio-based electrochemical detection and its in vitro antimicrobial activity
    (Elsevier Science Sa, 2016) Maiga, Mohomodou; Yalcinkaya, Esra Evrim; Sonmez, Burak; Puglia, Debora; Yavuz, Murat; Demirkol, Dilek Odaci; Kenny, Jose M.
    A novel support material for enzyme immobilization based on cetyltrimethylammonium bromide modified Dellite (CTAB-Del) was successfully synthesized and used to manufacture pyranose oxidase (PyOx) biosensors (CTAB-Del/PyOx). The intercalation of CTAB into Dellite was confirmed by FTIR, XRD and TGA techniques. PyOx was immobilized onto the glassy carbon electrode, via glutaraldehyde crosslinking, by using CTAB-Del as a support. In order to test the analytical performance of CTAB-Del/PyOx biosensors, chronoamperometric measurements were carried out using three electrodes configurations, at a constant potential of 0.7 V in working buffer, under stirring, with successive addition of glucose. The linear response for CTAB-Del/PyOx biosensor ranged from 0.01 to 0.50 mM with an equation of y=4.42x+0.004 (R-2=0.998), and the limit of detection for glucose was calculated to be 0.081 pM (S/N = 3). In order to confirm its practical use, the CTAB-Del/PyOx biosensor was also applied for glucose measurement in various beverages. In addition, the antimicrobial activities of Del and CTAB-Del were screened in vitro by means of the disc diffusion susceptibility test, selecting a yeast, three different Gram-positive, and five different Gram-negative bacteria. The obtained results showed a moderate antibacterial activity of CTAB-Del against Gram-positive bacteria. (C) 2016 Elsevier B.V. All rights reserved.
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    Electrochemical deposition of polypeptides: bio-based covering materials for surface design
    (Royal Soc Chemistry, 2014) Akbulut, Huseyin; Yavuz, Murat; Guler, Emine; Demirkol, Dilek Odaci; Endo, Takeshi; Yamada, Shuhei; Timur, Suna
    A simple and efficient approach for the electrochemical deposition of polypeptides as bio-based covering materials for surface design is described. The method involves N-carboxyanhydride (NCA) ring-opening polymerization from its precursor to form a thiophene-functionalized polypeptide macromonomer (T-Pala), followed by electropolymerization. The obtained conducting polymer, namely polythiophene-g- polyalanine (PT-Pala), was characterized and utilized as a matrix for biomolecule attachment. The biosensing applicability of PT-Pala was also investigated by using glucose oxidase (GOx) as a model enzyme to detect glucose. The designed biosensor showed a very good linearity for 0.01-1.0 mM glucose. Finally, the antimicrobial activities of newly synthesized T-Pala and PT-Pala were also evaluated by using the disc diffusion method.