Potassium Ion Fluorescence Probes: Structures, Properties and Bioimaging

Abstract

As one of the most important minerals in the body, potassium is vital for the heart and neurons. Methods that can noninvasively and accurately monitor changes in potassium balances would benefit disease diagnoses as well as offer insight into pathologies. Among the sensing approaches, fluorescent probes serve as a unique detection method for its simplicity, tunable detection range, and bioimaging ability. The design of new probes with highly selective K + receptors and transduction functionality remains a challenge that is motivated by numerous sensing and detection applications. In this minireview, fluoroionophores are summarized that undergo transduction, producing fluorescence signals when interacting with, e. g., potassium ions. The properties of ionophores (afford selective interaction with potassium) and fluorophores (generate signal read-out) are discussed. Molecular structure design and sensing mechanisms are included along with cell imaging applications. The selectivity towards K + and the absorption/ emission characteristics of the probes are of particular interest.

Fluorescent cyclophanes and their applications

“…178 For example, crown ethers 179 bearing aromatic rings, such as the widely known, dibenzo[24]crown-8, are cyclophanes. Thus, emissive crown ether cyclophanes possessing fluorophores in their core 180 or as pendant groups 181 have been designed and applied in the creation of probes 182 and supramolecular polymers. 183 Furthermore, some tiny cyclophanes—called [2.2]paracyclophanes 184 —which are composed of two phenylene rings linked in their para position by bismethylene bridges, were first described by Brown and Farthing 185 in 1949.…”

Methods of Measuring Mitochondrial Potassium Channels: A Critical Assessment

“…All these procedures introduce the methodological difficulties mentioned in previous sections. Hence, techniques for measuring mitochondrial potassium ion (and other alkali metal ion) trafficking have been intensively investigated for many years [58,59] with help of fluorescent indicators. Unfortunately, most of these fluorescent indicators suffer from limited specificity for K + , low dynamic range, difficulty of loading into cells, no selective targeting to mitochondria, and toxicity.…”

A BODIPY‐Based Far‐Red‐Absorbing Fluorescent Probe for Hypochlorous Acid Imaging

“…Therefore, various BODIPY derivatives are developed as photodynamic therapy agents, photocatalysts, and optical sensors. For instance, BODIPY‐based probes have been developed for detecting metal ions, [27,28] pH, [29] reactive oxygen species, [30–34] biothiols, [35,36] and completing drug release upon light irradiation [37] . These BODIPY‐based fluorescence probes have been playing an important role for the detection of analytes in biological environments [38–47] .…”