Applications of the Fluorescent False Neurotransmitter FFN102, an analog of biogenic neurotransmi... more Applications of the Fluorescent False Neurotransmitter FFN102, an analog of biogenic neurotransmitters and a suitable probe for coupled amperometry and TIRFM (total internal reflexion fluorescence microscopy) investigations of exocytotic secretion, were considered here. The electroactivity of FFN102 was shown to very likely arise from the oxidation of its phenolic group through a CE (Chemical-Electrochemical) mechanism. Evidences that the aminoethyl group of FFN102 is the key recognition element by BON N13 cells were also provided. Amperometric measurements were then performed at the single cell level with carbon fiber electrode (CFE) or Indium Tin Oxide (ITO) surfaces. It proved the disparity of kinetic and quantitative parameters of FFN102-stained cells acquired either at cell top and bottom. Moreover, coupled analyses of FFN102 loaded vesicles allowed us to classify three types of optical signals that probably arise from secretion releases thanks to their concomitant detection wi...
Electrochemical properties of plutonium (iv and vi) extracted in tributylphosphate from nitric ac... more Electrochemical properties of plutonium (iv and vi) extracted in tributylphosphate from nitric acid aqueous solutions are explored.
Angewandte Chemie (International ed. in English), Jan 20, 2017
In this work, Fluorescent False Neurotransmitter 102 (FFN102), a synthesized analogue of biogenic... more In this work, Fluorescent False Neurotransmitter 102 (FFN102), a synthesized analogue of biogenic neurotransmitters, was demonstrated to show both pH-dependent fluorescence and electroactivity. To study secretory behaviors at the single-vesicle level, FFN102 was employed as a new fluorescent/electroactive dual probe in a coupled technique (amperometry and total internal reflection fluorescence microscopy (TIRFM)). We used N13 cells, a stable clone of BON cells, to specifically accumulate FFN102 into their secretory vesicles, and then optical and electrochemical measurements of vesicular exocytosis were experimentally achieved by using indium tin oxide (ITO) transparent electrodes. Upon stimulation, FFN102 started to diffuse out from the acidic intravesicular microenvironment to the neutral extracellular space, leading to fluorescent emissions and to the electrochemical oxidation signals that were simultaneously collected from the ITO electrode surface. The correlation of fluorescenc...
Chemistry (Weinheim an der Bergstrasse, Germany), Jan 17, 2017
Electrochemistry and confocal fluorescence microscopy were successfully combined to selectively b... more Electrochemistry and confocal fluorescence microscopy were successfully combined to selectively bleach and monitor the fluorescence of NBD-labelled phospholipids of giant liposomes. Three types of giant unilamellar vesicles have been investigated, the fluorescent phospholipids being localized either mainly on their outer-, inner-, or both inner/outer leaflets. We established that only the fluorescent lipids incorporated in the outer leaflet of the vesicles underwent electrochemical bleaching upon reduction. The relative fluorescence intensity decay was quantified all along the electrochemical extinction through an original Fluorescence Loss In Electrobleaching (FLIE) assay. As expected, the re-organization of the fluorescent phospholipids followed diffusion-driven dynamics. This was also evidenced by comparison with Fluorescence Loss In Photobleaching (FLIP) and the corresponding numerical model. The value of the lateral diffusion coefficient of phospholipids was found to be similar...
ABSTRACT This work investigates the electrochemical behavior of Ce(IV) complexes extracted in ntr... more ABSTRACT This work investigates the electrochemical behavior of Ce(IV) complexes extracted in ntributylphosphate (TBP) from nitric aqueous solutions as an entry to the direct electrochemical characterization of plutonium in organic extractants related to nuclear fuel reprocessing. Ce(IV) complexes displayed a reversible electrochemical reduction wave in TBP, which could be observed only at glassy carbon electrodes. At slow scan rates, that reduction wave showed a Nernstian dependence on the logarithm of both nitric acid and TBP concentrations in the organic phase, featuring the exchange of nitrates and TBP upon reduction to Ce(III). The presence of increasing amounts of a common degradation product of TBP, such as hydrodibutyl phosphate (HDBP) caused the splitting of the original Ce(IV) reduction wave, as well as a shift towards more negative potential values, a behavior consistent with the formation of HDBP-Ce (IV) complexes.
ABSTRACT Three-electrode micro-cells equipped with a conventional reference electrode (SCE) were ... more ABSTRACT Three-electrode micro-cells equipped with a conventional reference electrode (SCE) were easily constructed based on micro-volume droplets suspended by capillary forces to the fritted glass of the SCE bridge. Working and counter electrodes were simply inserted through the droplet surface, allowing classical electrochemistry to be readily performed in minute samples.
... Mohamed Mellah, Eric Labbé*, Jean-Yves Nédélec and Jacques Périchon. Laboratoire d'Elect... more ... Mohamed Mellah, Eric Labbé*, Jean-Yves Nédélec and Jacques Périchon. Laboratoire d'Electrochimie, Catalyse et Synthèse Organique (LECSO; CNRS ... 3-hexylthiophene), since this particular material has been widely characterised by the groups of both McCullough3 and ...
Applications of the Fluorescent False Neurotransmitter FFN102, an analog of biogenic neurotransmi... more Applications of the Fluorescent False Neurotransmitter FFN102, an analog of biogenic neurotransmitters and a suitable probe for coupled amperometry and TIRFM (total internal reflexion fluorescence microscopy) investigations of exocytotic secretion, were considered here. The electroactivity of FFN102 was shown to very likely arise from the oxidation of its phenolic group through a CE (Chemical-Electrochemical) mechanism. Evidences that the aminoethyl group of FFN102 is the key recognition element by BON N13 cells were also provided. Amperometric measurements were then performed at the single cell level with carbon fiber electrode (CFE) or Indium Tin Oxide (ITO) surfaces. It proved the disparity of kinetic and quantitative parameters of FFN102-stained cells acquired either at cell top and bottom. Moreover, coupled analyses of FFN102 loaded vesicles allowed us to classify three types of optical signals that probably arise from secretion releases thanks to their concomitant detection wi...
Electrochemical properties of plutonium (iv and vi) extracted in tributylphosphate from nitric ac... more Electrochemical properties of plutonium (iv and vi) extracted in tributylphosphate from nitric acid aqueous solutions are explored.
Angewandte Chemie (International ed. in English), Jan 20, 2017
In this work, Fluorescent False Neurotransmitter 102 (FFN102), a synthesized analogue of biogenic... more In this work, Fluorescent False Neurotransmitter 102 (FFN102), a synthesized analogue of biogenic neurotransmitters, was demonstrated to show both pH-dependent fluorescence and electroactivity. To study secretory behaviors at the single-vesicle level, FFN102 was employed as a new fluorescent/electroactive dual probe in a coupled technique (amperometry and total internal reflection fluorescence microscopy (TIRFM)). We used N13 cells, a stable clone of BON cells, to specifically accumulate FFN102 into their secretory vesicles, and then optical and electrochemical measurements of vesicular exocytosis were experimentally achieved by using indium tin oxide (ITO) transparent electrodes. Upon stimulation, FFN102 started to diffuse out from the acidic intravesicular microenvironment to the neutral extracellular space, leading to fluorescent emissions and to the electrochemical oxidation signals that were simultaneously collected from the ITO electrode surface. The correlation of fluorescenc...
Chemistry (Weinheim an der Bergstrasse, Germany), Jan 17, 2017
Electrochemistry and confocal fluorescence microscopy were successfully combined to selectively b... more Electrochemistry and confocal fluorescence microscopy were successfully combined to selectively bleach and monitor the fluorescence of NBD-labelled phospholipids of giant liposomes. Three types of giant unilamellar vesicles have been investigated, the fluorescent phospholipids being localized either mainly on their outer-, inner-, or both inner/outer leaflets. We established that only the fluorescent lipids incorporated in the outer leaflet of the vesicles underwent electrochemical bleaching upon reduction. The relative fluorescence intensity decay was quantified all along the electrochemical extinction through an original Fluorescence Loss In Electrobleaching (FLIE) assay. As expected, the re-organization of the fluorescent phospholipids followed diffusion-driven dynamics. This was also evidenced by comparison with Fluorescence Loss In Photobleaching (FLIP) and the corresponding numerical model. The value of the lateral diffusion coefficient of phospholipids was found to be similar...
ABSTRACT This work investigates the electrochemical behavior of Ce(IV) complexes extracted in ntr... more ABSTRACT This work investigates the electrochemical behavior of Ce(IV) complexes extracted in ntributylphosphate (TBP) from nitric aqueous solutions as an entry to the direct electrochemical characterization of plutonium in organic extractants related to nuclear fuel reprocessing. Ce(IV) complexes displayed a reversible electrochemical reduction wave in TBP, which could be observed only at glassy carbon electrodes. At slow scan rates, that reduction wave showed a Nernstian dependence on the logarithm of both nitric acid and TBP concentrations in the organic phase, featuring the exchange of nitrates and TBP upon reduction to Ce(III). The presence of increasing amounts of a common degradation product of TBP, such as hydrodibutyl phosphate (HDBP) caused the splitting of the original Ce(IV) reduction wave, as well as a shift towards more negative potential values, a behavior consistent with the formation of HDBP-Ce (IV) complexes.
ABSTRACT Three-electrode micro-cells equipped with a conventional reference electrode (SCE) were ... more ABSTRACT Three-electrode micro-cells equipped with a conventional reference electrode (SCE) were easily constructed based on micro-volume droplets suspended by capillary forces to the fritted glass of the SCE bridge. Working and counter electrodes were simply inserted through the droplet surface, allowing classical electrochemistry to be readily performed in minute samples.
... Mohamed Mellah, Eric Labbé*, Jean-Yves Nédélec and Jacques Périchon. Laboratoire d'Elect... more ... Mohamed Mellah, Eric Labbé*, Jean-Yves Nédélec and Jacques Périchon. Laboratoire d'Electrochimie, Catalyse et Synthèse Organique (LECSO; CNRS ... 3-hexylthiophene), since this particular material has been widely characterised by the groups of both McCullough3 and ...
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