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    “Biomimetic-electrochemical-sensory-platform” for biomolecule free cocaine testing
    (Elsevier Ltd, 2018) Yilmaz Sengel T.; Guler E.; Arslan M.; Gumus Z.P.; Sanli S.; Aldemir E.; Akbulut H.; Odaci Demirkol D.; Coskunol H.; Timur S.; Yagci Y.
    A biomimetic cocaine sensor was fabricated by using poly(p-phenylene) (PPP) with cyclodextrin (CD) units in the backbone and poly(ethylene glycol) (PEG) side chains (PPP-CD-g-PEG). The sensory platform was constructed by one step surface modification of glassy carbon electrode with PPP-CD-g-PEG by drop coating. The electrochemical measurements are based on the formation of CD-cocaine inclusion complex on the surface resulting in a significant decrease in electron transfer capacity of the selected redox probe. The changes in the surface features due to cocaine binding were explored via electrochemical techniques such as differential pulse voltammetry, cyclic voltammetry and electrochemical impedance spectrometry. The sensor exhibited linearity in the range of 25–200 nM cocaine, LOD was calculated as 28.62 nM (n = 5) according to 3Sb/m formula. Finally, the sensory platform was successfully applied for the cocaine analysis in synthetic urine samples and correlated with the chromatographic method. © 2018 Elsevier B.V.
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    Double fluorescence assay via a ß-cyclodextrin containing conjugated polymer as a biomimetic material for cocaine sensing
    (Royal Society of Chemistry, 2017) Arslan M.; Yilmaz Sengel T.; Guler E.; Gumus Z.P.; Aldemir E.; Akbulut H.; Coskunol H.; Timur S.; Yagci Y.
    A double fluorescence µ-well assay that exploits a novel conjugated polymer containing cyclodextrin (CD) as the key component is reported. For the construction of the cocaine bioassay, poly(p-phenylene) with CD units in the main-chain and poly(ethylene glycol) side chains (PPP-CD-g-PEG) was first prepared by Suzuki coupling polymerization and coated on each well as a biomimetic material. Although the polyphenylene backbone is responsible for the fluorescence properties without an additional fluorophore, PEG and CD provide water solubility and selective complexation with cocaine, respectively. A cocaine antibody was used as a secondary recognition compound after labelling with quantum dots (QDs). Most notably, we show that the two-color fluorescence nature of the assay facilitates double measurement from the same sample and the described strategy can be adapted to various sensing systems. This journal is © The Royal Society of Chemistry.
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    An immunoelectrochemical platform for the biosensing of ‘Cocaine use’
    (Elsevier B.V., 2017) Yilmaz Sengel T.; Guler E.; Gumus Z.P.; Aldemir E.; Coskunol H.; Akbulut H.; Goen Colak D.; Cianga I.; Yamada S.; Timur S.; Endo T.; Yagci Y.
    In the present work, we demonstrate a novel surface design by combination of benzoylecgonine (BE) antibody and poly-L-phenylalanine bearing electroactive macromonomer (EDOT-BTDA-PPhe). This system served as an electro-immunosensor platform for the analysis of cocaine use by detecting both BE and cocaine. To construct the immunosensor, a glassy carbon electrode was covered with EDOT-BTDA-PPhe. Subsequently, BE antibody was immobilized on the polypeptide chains. The surface modifications were confirmed by electrochemical techniques. The immunosensor was used for the electrochemical detection of BE and cocaine as evidence of drug addiction. For both analytes, linearity was obtained between 0.5–25 µM. Finally, the proposed system was successfully employed for the analysis of synthetic biological fluids. © 2017 Elsevier B.V.