Quantal Release Analysis of Electrochemically Active Molecules Using Single-Cell Amperometry

Enhancing the Study of Quantal Exocytotic Events: Combining Diamond Multi-Electrode Arrays with Amperometric PEak Analysis (APE) an Automated Analysis Code

“…Amperometry provides a real-time measurement of the exocytotic events, with the limitation that it can only reveal electrochemically oxidizable molecules, such as catecholamines [8,9]. This technique has a high sensitivity, allowing the estimation of released molecules by individual vesicles since the intensity of the signal is proportional to the collected electrons.…”

“…This technique takes advantage of an electrode, polarized at an appropriate bias with respect to the cellular medium, placed close (in contact) to the cel membrane to measure the current generated by the transfer of electrons following the oxidation of the molecule directly on the sensing electrode. Amperometry provides a real-time measurement of the exocytotic events, with the limitation that it can only reveal electrochemically oxidizable molecules, such as catecholamines [8,9]. This technique has a high sensitivity, allowing the estimation o released molecules by individual vesicles since the intensity of the signal is proportiona to the collected electrons.…”

An Ultramicroelectrode Electrochemistry and Surface Plasmon Resonance Coupling Method for Cell Exocytosis Study

“…It is found that the exocytosis of nerve cells directly affects brain functions such as cognition, decision-making, learning, memory, etc. − Anomalies in the release of neurotransmitters, including variations in the type, quantity, and frequency of exocytosis, can lead to various brain-related diseases. Therefore, a method capable of obtaining information on exocytosis in many aspects holds great significance for pathological research, disease prevention, diagnosis, and treatment …”

“…UME electrochemistry is the most commonly used method to study electroactive substances released during exocytosis, such as neurotransmitters. − The electrodes, with diameters ranging from micrometers to nanometers, are positioned near or inserted into the cell by using microscopic devices. The electroactive substances react on the electrode surface, generating redox peaks or current spikes, allowing for the determination of kinetics, chemical information, and substance concentrations released during exocytosis. ,, Among the existing ultramicroelectrodes, the carbon nanopipette (CNP) electrode has a cavity geometry similar to a microcollection bottle, which can reduce the diffusion loss of released neurotransmitters. − In addition, CNP electrodes are easy to prepare and modify and have an adjustable electroactive area. Therefore, they have been widely used in exocytosis studies. ,− While those methods provide a tremendous amount of valuable information about single cell and individual event, it is not enough to obtain only single-cell exocytosis information in many cases, just like in the pharmaceutical industry, in which it is necessary to test the response of candidate drugs to cell cultures and even organisms, rather than just evaluating their impact on a single target molecule .…”

“…Therefore, a method capable of obtaining information on exocytosis in many aspects holds great significance for pathological research, disease prevention, diagnosis, and treatment. 6 Several methods have been developed for exocytosis research, including fluorescence microscopy imaging (FMI) techniques, electrophysiological methods, ultramicroelectrode (UME) electrochemistry methods, etc. FMI techniques employ fluorescent labeling of intracellular vesicles to visualize and track vesicle movement in real time during exocytosis, facilitating the study of the vesicle release process.…”