Yazar "Ulucay, Sude" seçeneğine göre listele

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    A novel acetylcholinesterase inhibition based colorimetric biosensor for the detection of paraoxon ethyl using CUPRAC reagent as chromogenic oxidant
    (Elsevier B.V., 2024) Ayaz, Selen; Ulucay, Sude; Uzer, Ayşem; Dilgin, Yusuf; Apak, Reşat
    A novel colorimetric biosensor for the sensitive and selective detection of an organophosphate pesticide, paraoxon ethyl (POE), was developed based on its inhibitory effect on the acetylcholine esterase (AChE) enzyme. The bis-neocuproine copper (II) complex ([Cu(Nc)2]2+) known as the CUPRAC reagent, was used as a chromogenic oxidant in the AChE inhibition-based biosensors for the first time. To initiate the biosensor, an enzymatic reaction takes place between AChE and its substrate acetylthiocholine (ATCh). Then, enzymatically produced thiocholine (TCh) reacts with the light blue [Cu(Nc)2]2+ complex, resulting in the oxidation of TCh to its disulfide form. On the other hand, [Cu(Nc)2]2+ reduces to a yellow-orange cuprous complex ([Cu(Nc)2]+) which gives maximum absorbance at 450 nm. However, the absorbance of [Cu(Nc)2]+ proportionally decreased with the addition of POE because the inhibition of AChE by the organophosphate pesticide reduced the amount of TCh that would give a colorimetric reaction with the CUPRAC reagent. Based on this strategy, the linear response range of a colorimetric biosensor was found to be between 0.15 and 1.25 μM with a detection limit of 0.045 μM. The fabricated biosensor enabled the selective determination of POE in the presence of some other pesticides and metal ions. The recovery results between 92% and 104% were obtained from water and soil samples spiked with POE, indicating that the determination of POE in real water and soil samples can be performed with this simple, accurate, sensitive, and low-cost colorimetric biosensor.
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    Öğe
    Light-Induced Performance Enhancement of Supercapacitors through Thiol-Ene Click Surface Functionalization of Thienothiophene-BODIPY Porous Polymers
    (Amer Chemical Soc, 2025) Ozdemir, Mucahit; Ulucay, Sude; Sevimli, Esra; Altinisik, Sinem; Koksoy, Baybars; Yalcin, Bahattin; Koyuncu, Sermet
    Photoassisted supercapacitors are emerging as next-generation energy storage devices that synergistically combine light harvesting and electrochemical energy storage. BODIPY-based semiconductors, known for their strong light absorption, tunable electronic properties, and photostability, have recently attracted attention as efficient photoactive components in such systems. This study investigates the potential use of cross-linked thieno[3,2-b]thiophene-BODIPY polymer as an electrode material for photoassisted supercapacitors, prepared through a surface functionalization approach using thiol-ene click chemistry. The polymer exhibited broad-band absorption and a low band gap due to extended conjugation, as confirmed by UV-vis and fluorescence spectroscopy, along with comprehensive optical, electrochemical, and morphological characterization. DFT calculations showed that the HOMO-LUMO energy gap narrows under illumination, indicating improved charge transport. Cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) measurements confirmed that the cross-linked polymer offers high capacitance, low internal resistance, and long cycle stability. In terms of supercapacitor performance, a photoinduced enhancement of up to 50% in specific capacitance was observed under light. At a current density of 1.0 A/g, the specific capacitance increased from 240 F/g in the dark to 362 F/g under illumination. Stability tests conducted over 2000 cycles demonstrated that the supercapacitor retained 90% of its initial capacitance.
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    Öğe
    Photopolymerized PEDOT-coated polydopamine: A Green approach for supercapacitor electrode materials
    (Elsevier, 2025) Ermis, Sena; Tohtayeva, Jahan; Altinisik, Sinem; Ulucay, Sude; Jockusch, Steffen; Kiskan, Baris; Koyuncu, Sermet
    Conjugated conductive polymers (CCPs) are promising electrode materials for next-generation supercapacitors (SCs), yet their scalable and eco-friendly synthesis remains a challenge. Here, we report a light-driven, in-situ polymerization of EDOT onto polydopamine (PDA@PEDOT), offering a sustainable, photoinitiated route for high-performance SC electrodes. Using an organic, environmentally safe photoinitiator and ethanol as a green solvent, this method achieves uniform PEDOT deposition on PDA with minimal energy input. Using a three-electrode method, the resulting PDA@PEDOT electrode exhibits exceptional electrochemical performance, including a high specific capacitance of 275 F g-1 at 1.0 A g-1, an energy density of 34.04 W h kg-1, and excellent adhesion properties. The synergistic non-covalent interactions between PDA's amine, catechol, quinone functionalities and PEDOT are credited to enhance ion transport through the electrode, improving SC efficiency. These exceptional properties, alongside strong adhesion and uniform deposition of PEDOT on PDA, demonstrate the novelty of the advanced photopolymerization approach. Our eco-friendly photopolymerization method paves the way for sustainable, high-performance SC electrode fabrication, bridging the gap between sustainable chemistry and next-generation energy storage.