Browsing by Author "Vandeput, Marie"

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Flow-Through Enzyme Immobilized Amperometric Detector for the Rapid Screening of Acetylcholinesterase Inhibitors by Flow Injection Analysis
(Elsevier Science Bv, 2015) Vandeput, Marie; Parsajoo, Cobra; Vanheuverzwijn, Jerome; Patris, Stephanie; Yardim, Yavuz; le Jeune, Alexandre; Kauffmann, Jean-Michel
A commercially available thin-layer flow-through amperometric detector, with the sensing block customized in an original design, was applied to the screening of drug compounds known as acetylcholinesterase (AChE) inhibitors. AChE from electric eel was covalently immobilized onto a cysteamine modified gold disk adjacent to a silver disk working electrode. On-line studies were performed by flow injection analysis (FIA) in PBS buffer pH 7.4. Seven commercially available AChE inhibitors used in the medical field, namely neostigmine, eserine, tacrine, donepezil, rivastigmine, pyridostigmine and galantamine as well as two natural compounds, quercetin and berberine, were investigated. The same trend of inhibitory potency as described in the literature was observed. Of particular interest and in addition to the determination of the IC50 values, this flow-through system allowed the study of both, the stability of the enzyme-inhibitor complex and the kinetic of the enzyme activity recovery. (C) 2014 Elsevier B.V. All rights reserved.
A Reduced Graphene Oxide-Based Electrochemical Dna Biosensor for the Detection of Interaction Between Cisplatin and Dna Based on Guanine and Adenine Oxidation Signals
(Wiley-v C H verlag Gmbh, 2017) Yardim, Yavuz; Vandeput, Marie; Celebi, Metin; Senturk, Zuhre; Kauffmann, Jean-Michel
A glassy carbon electrode (GCE) was modified by electrochemically reduced graphene oxide (ERGO) for subsequent dsDNA immobilization. The interaction of cisplatin with dsDNA was studied at this modified electrode. Quantitative investigations were performed by adsorptive transfer stripping voltammetry (AdTSV) using differential pulse voltammetry (DPV). The morphology and structure of graphene oxide (GO) and ERGO modified GCEs (GO/GCE and ERGO/GCE, respectively) were characterized by UV-vis, FT-IR, Raman spectroscopy and cyclic voltammetry. Compared with the bare GCE and the GO/GCE, the ERGO/GCE exhibited excellent electrocatalytic activity towards the oxidation of dsDNA due to guanine and adenine groups, testified by high oxidation peak currents and decreased oxidation potentials. The interaction of micromolar concentrations of cisplatin with surface confined dsDNA was readily detected as inferred from the decrease of the voltammetric oxidation peaks of guanine and adenine. This trend was significantly greater at the ERGO/GCE compared to the GO/GCE. The interaction of cisplatin with dsDNA was also studied in solution phase by AdTSV with detection at the ERGO/GCE.