title: On the mechanism of electrochemical vesicle cytometry: chromaffin cell vesicles and liposomes.
abstract: The mechanism of mammalian vesicle rupture onto the surface of a polarized carbon fiber microelectrode during electrochemical vesicle cytometry is investigated. It appears that following adsorption to the surface of the polarized electrode, electroporation leads to the formation of a pore at the interface between a vesicle and the electrode and this is shown to be potential dependent. The chemical cargo is then released through this pore to be oxidized at the electrode surface. This makes it possible to quantify the contents as it restricts diffusion away from the electrode and coulometric oxidation takes place. Using a bottom up approach, lipid-only transmitter-loaded liposomes were used to mimic native vesicles and the rupture events occurred much faster in comparison with native vesicles. Liposomes with added peptide in the membrane result in rupture events with a lower duration than that of liposomes and faster in comparison to native vesicles. Diffusional models have been developed and suggest that the trend in pore size is dependent on soft nanoparticle size and diffusion of the content in the nanometer vesicle. In addition, it appears that proteins form a barrier for the membrane to reach the electrode and need to move out of the way to allow close contact and electroporation. The protein dense core in vesicles matrixes is also important in the dynamics of the events in that it significantly slows diffusion through the vesicle.
authors.affiliation: Chalmers University of Technology, Department of Chemistry and Chemical Engineering, Kemivägen 10, 412 96 Gothenburg, Sweden. andrewe@chalmers.se.
authors.forename: Jelena
authors.initials: J
authors.lastname: Lovrić
authors.affiliation: Chalmers University of Technology, Department of Chemistry and Chemical Engineering, Kemivägen 10, 412 96 Gothenburg, Sweden. andrewe@chalmers.se.
authors.forename: Neda
authors.initials: N
authors.lastname: Najafinobar
authors.affiliation: Chalmers University of Technology, Department of Chemistry and Chemical Engineering, Kemivägen 10, 412 96 Gothenburg, Sweden. andrewe@chalmers.se.
authors.forename: Johan
authors.initials: J
authors.lastname: Dunevall
authors.affiliation: University of Gothenburg, Department of Chemistry and Molecular Biology, Kemivägen 10, 412 96 Gothenburg, Sweden.
authors.forename: Soodabeh
authors.initials: S
authors.lastname: Majdi
authors.affiliation: Ecole Normale Supérieure-PSL Research University, Département de Chimie, Sorbonne Universités-UPMC Univ. Paris 06, CNRS UMR 8640 PASTEUR, 24 rue Lhomond, 75005 Paris, France.
authors.forename: Irina
authors.initials: I
authors.lastname: Svir
authors.affiliation: Ecole Normale Supérieure-PSL Research University, Département de Chimie, Sorbonne Universités-UPMC Univ. Paris 06, CNRS UMR 8640 PASTEUR, 24 rue Lhomond, 75005 Paris, France.
authors.forename: Alexander
authors.initials: A
authors.lastname: Oleinick
authors.affiliation: Ecole Normale Supérieure-PSL Research University, Département de Chimie, Sorbonne Universités-UPMC Univ. Paris 06, CNRS UMR 8640 PASTEUR, 24 rue Lhomond, 75005 Paris, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Amatore
authors.affiliation: Chalmers University of Technology, Department of Chemistry and Chemical Engineering, Kemivägen 10, 412 96 Gothenburg, Sweden. andrewe@chalmers.se and University of Gothenburg, Department of Chemistry and Molecular Biology, Kemivägen 10, 412 96 Gothenburg, Sweden.
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Ewing
mesh_terms: D000327:Adsorption; D000818:Animals; D019439:Chromaffin Cells / Q000737:chemistry*; D004058:Diffusion; D018274:Electroporation; D005089:Exocytosis; D000067128:Extracellular Vesicles / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry*; D018377:Neurotransmitter Agents / Q000737:chemistry; D010084:Oxidation-Reduction
chemical_list: D008081:Liposomes; D018377:Neurotransmitter Agents