Electrochemical Fluorescence Switch of Organic Fluorescent or Fluorogenic Molecules

Abstract

This short review is aimed at emphasizing the most prominent recent works devoted to the fluorescence modulation of organic fluorescent or fluorogenic molecules by electrochemistry. This still expanding research field not only addresses the smart uses of known molecules or the design of new ones, but also investigates the development of instrumentation providing time-and space-resolved information at the molecular level. Important considerations including fluorescent/fluorogenic probes, reversible/irreversible fluorescence switch, direct/indirect fluorescence modulation, or environment properties are especially scrutinized in recent works dealing with bioanalysis perspectives.

Survey of Recent Advances in Molecular Fluorophores, Unconjugated Polymers, and Emerging Functional Materials Designed for Electrofluorochromic Use

“…The scope of this survey concerns the consolidation of the recent progress in the materials design of organic electrofluorochromic materials. Given the breadth of emissive materials for both electrofluorochromic [ 33 , 34 , 35 , 36 , 37 , 38 , 39 ] and electroluminochromic [ 40 , 41 , 42 , 43 , 44 , 45 ] applications that have been reviewed, advances made towards developing EFC materials that span the past five years are surveyed herein. Within this context, focus will be placed on materials whose emission is reversibly quenched with an applied potential according to three broad categories of electrofluorochromes: (1) molecular fluorophores coupled with redox-active moieties, (2) electroactive molecular fluorophores, and (3) unconjugated organic redox-active emissive polymers.…”

Visualisation of electrochemical processes by coupled electrochemistry and fluorescence microscopy

“…EC-fluorescence requires the use of fluorogenic probes whose fluorescence properties are sensitive to the electrochemical process of interest. These probes are broadly classified into two categories depending on whether these undergo a direct or an indirect electrochemical modulation between the luminescent and non-luminescent state [5,31]. The direct modulation (Scheme 2a) implies that the fluorescent species is itself electroactive and that the fluorescence characteristics depend upon its redox state.…”

“…Different families of fluorophore and different switching mechanisms are known, and the interested reader is referred to a recent review on the topic [31]. Hereafter, we focus on the specificities of the fluorogenic probes employed in the works described in the previous section.…”

Interplay between electrochemistry and optical imaging: The whole is greater than the sum of the parts

“…A last alternative is offered by Amplex Red, a well-known DH derivative, which is air stable to obtain a fluorescence increase upon an electrochemical oxidation [22]. Following a comparable strategy, the use of several other electrofluorogenic dyes is also possible and was recently reviewed by Buriez and co-workers [23].…”