Vesicular exocytosis and microdevices – microelectrode arrays

Abstract

Among all the analytical techniques capable of monitoring exocytosis in real time at the single cell level, electrochemistry (particularly amperometry at a constant potential) using ultramicroelectrodes has been demonstrated to be an important and convenient tool for more than two decades. Indeed, because the electrochemical sensor is located in the close vicinity of the emitting cell ("artificial synapse" configuration), much data can be gathered from the whole cell activity (secretion frequency) to the individual vesicular release (duration, fluxes or amount of molecules released) with an excellent sensitivity. However, such a single cell analysis and its intrinsic benefits are at the expense of the spatial resolution and/or the number of experiments. The quite recent development of microdevices/microsystems (and mainly the microelectrode arrays (MEAs)) offers in some way a complementary approach either by combining spectroscopy-microscopy or by implementing a multianalysis. Such developments are described and discussed in the present review over the 2005-2014 period.

A Dual Functional Electroactive and Fluorescent Probe for Coupled Measurements of Vesicular Exocytosis with High Spatial and Temporal Resolution

“…The implementation of TIRFM/amperometry coupling measurements relies mainly on the specific property of the working electrode, which allows both electrochemical recording and fluorescence imaging at the same time (Scheme a). Accordingly, the material used for the working electrode must be transparent and electrically conductive . In this context, a microdevice (Scheme b) with eight independent ITO electrodes was fabricated (Scheme S1).…”

Indium Tin Oxide Microsystem for Electrochemical Detection of Exocytosis of Migratory Dendritic Cells

“…We propose that our experiments will identify specific modes of exocytosis and will display the mutual interaction of endocytic and exocytotic trafficking of DCs as well as will quantitatively analyzing exocytosis during cell migration. In addition, further optimization of our microdevice based on transparent ITO microelectrode should facilitate future real‐time combining assays of DCs’ exocytotic behaviors with other fluorescence technology . By doing so, correlations between place (on the DC surface, rear or front) or size of vesicles (lysosomes, macropinosomes etc…) and quantitative parameters of secretion could be drawn.…”

Multianalyte Physiological Microanalytical Devices

“…Exocytosis of redox active species can be measured potentiometrically or amperometrically (29) and has led to numerous discoveries in vesicle transport (29)(30)(31)(32)(33). For example, measurements of the relative concentrations of specific analytes, including octopamine, following release were reported (30).…”

“…For example, measurements of the relative concentrations of specific analytes, including octopamine, following release were reported (30). Although it is not always possible to differentiate the molecules released, the timing and frequency of events marked by the release of neurotransmitters have been recorded (31), and microelectrode arrays allow for both single-cell and population analyses (32). Additionally, the initial pore size before full release has been mathematically modeled using experimentally determined parameters (31).…”