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    Biomimetic-electrochemical-sensory-platform for biomolecule free cocaine testing
    (Elsevier Science Bv, 2018) Sengel, Tulay Yilmaz; Guler, Emine; Arslan, Mustafa; Gumus, Z. Pinar; Sanli, Serdar; Aldemir, Ebru; Akbulut, Huseyin; Demirkol, Dilek Odaci; Coskunol, Hakan; Timur, Suna; Yagci, Yusuf
    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.
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    "Biomimetic-electrochemical-sensory-platform" for biomolecule free cocaine testing
    (Elsevier Science Bv, 2018) Sengel, Tulay Yilmaz; Guler, Emine; Arslan, Mustafa; Gumus, Z. Pinar; Sanli, Serdar; Aldemir, Ebru; Yagci, Yusuf
    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.
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    Double fluorescence assay via a beta-cyclodextrin containing conjugated polymer as a biomimetic material for cocaine sensing
    (Royal Soc Chemistry, 2017) Arslan, Mustafa; Sengel, Tulay Yilmaz; Guler, Emine; Gumus, Z. Pinar; Aldemir, Ebru; Akbulut, Huseyin; Coskunol, Hakan; Timur, Suna; Yagci, Yusuf
    A double fluorescence mu-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 poly-phenylene 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.
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    A Functional Platform for the Detection of JWH-073 as a Model for Synthetic Cannabinoids
    (Wiley-V C H Verlag Gmbh, 2018) Sengel, Tulay Yilmaz; Celik, Emine Guler; Aydogan, Cansu; Gumus, Zinar Pinar; Ilktac, Raif; Aydindogan, Eda; Ciftci, Mustafa; Aldemir, Ebru; Coskunol, Hakan; Timur, Suna; Yagci, Yusuf
    During the last decade, progress has been made in the on-site detection of abused drug use. Herein, we present an electrochemical biosensor for the detection of one of the synthetic cannabinoids (SCs), JWH-073, using poly (methyl methacrylate) (PMMA) hyperbranched copolymer (HBC) as a base coating and antibody molecules to bind the JWH-073 to the surface. Modification of the surface is proved with various techniques such as differential pulse voltammetry, cyclic voltammetry, and electrochemical impedance spectrometry. The limit of detection and linearity (in logarithmic scale) for JWH-073 were found to be 31.87 ng/mL and 25-500 ng/mL, respectively. The selectivity of the proposed biosensor was also tested in the presence of interfering molecules and the response was much higher for JWH-073 in all measurements. In the final part of the study, synthetic urine was tested with the device and the relative standard deviation value was calculated to be less than 5.0%. The confirmation of data from the resulting bio-platform was performed via LC-QTOF/MS. This work is the first of its kind, a novel, rapid, cost-effective sensing platform for the detection of the SC.
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    An immunoelectrochemical platform for the biosensing of 'Cocaine use'
    (Elsevier Science Sa, 2017) Sengel, Tulay Yilmaz; Guler, Emine; Gumus, Z. Pinar; Aldemir, Ebru; Coskunol, Hakan; Akbulut, Huseyin; Colak, Demet Goen; Cianga, Ioan; Yamada, Shuhei; Timur, Suna; Endo, Takeshi; Yagci, Yusuf
    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 mu M. Finally, the proposed system was successfully employed for the analysis of synthetic biological fluids. (C) 2017 Elsevier B.V. All rights reserved.
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    Mobile Phone Sensing of Cocaine in a Lateral Flow Assay Combined with a Biomimetic Material
    (Amer Chemical Soc, 2017) Guler, Emine; Sengel, Tulay Yilmaz; Gumus, Z. Pinar; Arslan, Mustafa; Coskunol, Hakan; Timur, Suna; Yagci, Yusuf
    Lateral flow assays (LFAs) are an ideal choice for drug abuse testing favored by their practicability, portability, and rapidity. LFA based on site rapid screening devices provide positive/negative judgment in a short response time. The conventionally applied competitive assay format used for small molecule analysis such as abused drugs restricts the quantitation ability of LFA strips. We report herein, for the first time, a new strategy using the noncompetitive assay format via a biomimetic material, namely, poly(p-phenylene) beta-cyclodextrin poly(ethylene glycol) (PPP-CD-g-PEG) combined with gold nanoparticle (AuNP) conjugates as the labeling agent to recognize the target cocaine molecule in the test zone. The intensities of the visualized red color in the test line indicate that the cocaine concentrations were analyzed via a smartphone application. Significantly, a combination of this platform with a smartphone application provides quantitative data on the cocaine amount, making it a very inventive and attractive approach especially for on-site applications at critical points such as traffic stops and the workplace.