Potassium Ion Fluorescence Probes: Structures, Properties and Bioimaging

As one of the most important minerals in the body, potassium is vital for the heart and neurons. Methods that can non-invasively 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.