Overview and outlook of the strategies devoted to electrofluorescence surveys: Application to single cell secretion analysis

Secretion of neurotransmitters and hormones via vesicular exocytosis is a fundamental biological field where physicochemical machinery is still source of controversy. Over the last decades, real-time tech-niques have been developed at the single cell level including electrochemistry (amperometry) and fluorescence (total internal reflection fluorescence microscopy). This review especially focuses on the expected fruitful fluoroelectrochemical combination. Analytical constraints (experimental set-up configuration, use of transparent electrodes, microdevices properties, cell models, structure and physicochemical properties of electrofluorescent probes, presence of orphan events) of the TIRFM-amperometry combination are commented. A special attention is paid about the recent design of new dual spectroelectrochemical biomolecules (fluorescent neural markers, fluorescent adducts, false fluorescent neurotransmitters). Despite significant advances, this challenging combinatorial research continues and new obstacles (reaching in the same molecule adequate fluorescent, electrochemical and biological target properties) need to be overcome thus giving the impression that the final purpose is currently so close and so far. (C) 2020 Elsevier B.V. All rights reserved.