Simultaneous Quantification of Vesicle Size and Catecholamine Content by Resistive Pulses in Nanopores and Vesicle Impact Electrochemical Cytometry

Abstract

We have developed the means to simultaneously measure the physical size and count catecholamine molecules in individual nanometer transmitter vesicles. This is done by combining resistive pulse (RP) measurements in a nanopore pipet and vesicle impact electrochemical cytometry (VIEC) at an electrode as the vesicle exits the nanopore. Analysis of freshly isolated bovine adrenal vesicles shows that the size and internal catecholamine concentration of vesicles varies with the occurrence of a dense core inside the vesicles. These results might benefit the understanding about the vesicles maturation, especially involving the “sorting by retention” process and concentration increase of intravesicular catecholamine. The methodology is applicable to understanding soft nanoparticle collisions on electrodes, vesicles in exocytosis and phagocytosis, intracellular vesicle transport, and analysis of electroactive drugs in exosomes.

Recent Progress in Quantitatively Monitoring Vesicular Neurotransmitter Release and Storage With Micro/Nanoelectrodes

“…In a recent report, Zhang et al combined the resistive pulse sensing with VIEC to simultaneously quantify the size and neurotransmitter content of individual nanoscale vesicles extracted from bovine adrenal glands (Zhang et al, 2020 ). As shown in Figure 13 , single vesicles initially placed in the glass pipette passing through the nanopore powered by a periodic pressure produce a resistive pulse which could reflect the vesicle size quantitatively.…”

“…Electroactive content of the vesicle is electrooxidized and generates a current spike. Reprinted from Zhang et al ( 2020 ), with permission from the American Chemical Society.…”

Chemical Analysis of Single Cells and Organelles

“…With a similar method, Zhang et al achieved one-to-one matching of resistive pulse spikes with catecholamine release spikes of single chromaffin vesicles ( Figure 1 C). 28 On the basis of this, single vesicular catecholamine concentrations were quantified, and a comparison between dense core vesicles and nondense core vesicles provided quantitative information about the vesicle maturation process. Very recently, Hu et al controlled orifice sizes of open CNPs to group different sized vesicles and quantified the corresponding vesicular content and release kinetics ( Figure 1 D).…”

Detection of individual conducting graphene nanoplatelet by electro-catalytic depression

“…Stochastic collision enables the detection of a wide variety of individual entities such as metal nanoparticles [1,2], emulsion droplets [3,4], vesicle [5,6], micelles [7], proteins [8] and bacteria [9]. Depending on the nature of the entity (insulator, conductor, redox-active material), various electrochemical detection schemes can be used [10].…”