Raphaël Trouillon

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The basis for communication between nerve cells lies in the process of exocytosis, the fusion of neurotransmitter filled vesicles with the cell membrane resulting in release of the signaling molecules. Even though much is known about this process, the extent that the vesicles are emptied upon fusion is a topic that is being debated. We have analyzed(More)
Dynamin is a GTPase mechanochemical enzyme involved in the late steps of endocytosis, where it separates the endocytotic vesicle from the cell membrane. However, recent reports have emphasized its role in exocytosis. In this case, dynamin may contribute to the control of the exocytotic pore, thus suggesting a direct control on the efflux of(More)
We present an amperometric study of content release from individual vesicles in an artificial secretory cell designed with the minimal components required to carry out exocytosis. Here, the membranes of the cell and vesicles are substituted for protein-free giant and large unilamellar vesicles respectively. In replacement of the SNARE-complex, the cell(More)
We have compared the properties and resistance to DA fouling of a carbon nanotube fiber (CNTF) microelectrode to a traditional carbon fiber (CF) microelectrode. These two materials show comparable electrochemical activities for outer-sphere and inner-sphere redox reactions. Although the CNTF might have a higher intrinsic RC constant, thus limiting its(More)
Magnetic micro- and nanoparticles ('magnetic beads') have been used to advantage in many microfluidic devices for sensitive antigen (Ag) detection. Today, assays that use as read-out of the signal the number count of immobilized beads on a surface for quantification of a sample's analyte concentration have been among the most sensitive and have allowed(More)
We describe the concept of magnetic particle-scanning for on-chip detection of biomolecules: a magnetic particle, carrying a low number of antigens (Ag's) (down to a single molecule), is transported by hydrodynamic forces and is subjected to successive stochastic reorientations in an engineered magnetic energy landscape. The latter consists of a pattern of(More)
We demonstrate a method to determine the Brownian motion and the diffusion coefficient of a nanoparticle in water in a plane that is parallel to a solid boundary and as function of the distance normal to that boundary by using an optical tweezers instrument. A solution of 190 nm-diameter fluorescent polystyrene nanoparticles in de-ionized (DI) water is(More)
During exocytosis, small quantities of neurotransmitters are released by the cell. These neurotransmitters can be detected quantitatively using electrochemical methods, principally with disk carbon fiber microelectrode amperometry. An exocytotic event then results in the recording of a current peak whose characteristic features are directly related to the(More)
1 Member of the ISE The diffusion layer is a critical factor affecting the temporal response of electrochemical devices. In this article, we have investigated the effect of the relaxation of the diffusion layer during the potentiodynamic sensing of ferrocenemethanol (FcMeOH) in microchannels and compared these results to amperometry. First, the effect of(More)