Browsing by Author "Cirpan, Ali"

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    A biosensor platform based on amine functionalized conjugated benzenediamine-benzodithiophene polymer for testosterone analysis
    (WILEY, 2020-01-01) Bulut, Umut; Sanli, Serdar; Cevher, Sevki Can; Cirpan, Ali; Donmez, Sude; Timur, Suna
    A novel benzenediamine-benzodithiophene polymer is synthesized for use in biosensor fabrication for the detection of testosterone. The sensory platform is constructed via drop coating on a screen-printed carbon electrode, using poly(benzenediamine-Bis{[}(2-ethylhexyl)oxy]benzodithiophene) (pBDBT) as the polymer layer. Testosterone antibodies are immobilized on the polymer-coated electrode surface via glutaraldehyde, which binds to the surface through the amino functional groups on the polymer backbone. The changes in the surface features due to testosterone binding are investigated via electrochemical techniques such as differential pulse voltammetry, cyclic voltammetry, and electrochemical impedance spectrometry as well as contact angle measurements. Surface morphology of the modified electrodes is characterized by atomic force microscopy. The linear range and limit of detection of the sensor are calculated. Impact of possible interfering compounds is investigated. Furthermore, the sensory platform is utilized for testosterone analysis in synthetic biological fluids.
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    Benzodithiophene bearing conjugated polymer-based surface anchoring for sensitive electrochemical glucose detection
    (BUDAPEST UNIV TECHNOL \& ECON, 2022-01-01) Bulut, Umut; Sayin, Vuslat Oyku; Cevher, Sevki Can; Cirpan, Ali; Soylemez, Saniye
    An amino-functionalized, conjugated polymer (P(BDBT)) modified glassy carbon electrode (GCE) was employed as an immobilization platform for glucose oxidase (GOx) enzyme to assemble a novel glucose biosensor. Amino groups available on the polymer backbone served as bioconjugation sites for GOx via glutaraldehyde (GA). The biosensor response to the reduction in oxygen amount because of the enzyme reaction was monitored at ???0.7 V potential versus Ag/AgCl. The biosensor displayed a broad linear range between 0.1???1.0 mM glucose with a detection limit of 0.17 mM. The values of the apparent Michaelis-Menten constant (KMapp) and sensitivity were determined as 1.74 mM, and 28.17 ??A/(mM??cm2), respectively. GOx immobilized P(BDBT) film displayed high stability, selectivity, and reproducibility. Cyclic voltammetry (CV) and Scanning electron microscopy (SEM) techniques were utilized for the characterization of surface modifications. The fabricated biosensor was adept at determining the amount of glucose in a commercial beverage. The simple electrochemical method for the construction of P(BDBT)/GOx biosensors could pave the way to new perspectives in developing profitable biosensors.