Highly K⁺‐Selective Fluorescent Probes for Lifetime Sensing of K⁺ in Living Cells

Abstract

What is the most significant result of this study?We designed and synthesized by "click" chemistry af luorescent probe consisting of the highly K + -selective N-(o-isopropoxy)phenylaza-18-crown-6 ionophore and of the bright [1,3] How did the collaborationo nt his project start?The collaboration between the Wessig and the Holdt group in Potsdam started after Wessig et al. announced af luorescence dye with ahigh quantum yield, ahigh fluorescence lifetime, and ah igh photostability in water (Chem. Eur.J .2013, 19,1 7349-17357), and Holdt et al. utilized the N-(o-isopropoxy)phenylaza-18-crown-6 as a highly K + selective building block to measure K + levels in vitro (Chem. Asian J. 2016, 11,2 41-247). P. M üller of the Humboldt university in Berlin joined this research project to study K + levels in vivo. What future opportunities do you see?Beside the selective K + determination in vivo, we are also designing fluorescence lifetime probes for other biological important cations such as Na + and Ca 2 + by using this promising approach.

1,2,3‐Triazol‐1,4‐diyl‐Fluoroionophores for Zn2+, Mg2+ and Ca2+ based on Fluorescence Intensity Enhancements in Water

“…These φ f values are low, caused by a PET process from the aniline unit to the coumarin moiety, which quenches the fluorescence. Further, similar low φ f values were also found for a set of π ‐conjugated 1,2,3‐triazol‐1,4‐diyl–fluoroionophores [11a–e,12a−c] . Herein, the regioisomeric triazole linkage in Zn1 is responsible for a better fluorescence quenching than in Zn3 .…”

“…Zn1 and Zn3 ). In the UV/Vis‐absorption spectra of Zn1 , Zn2 , Zn3 and Zn4 a second CT absorption at around 287 nm ( ZN1 ), at around 289 nm ( Zn2 ), at around 312 nm ( Zn3 ) and at around 311 nm ( Zn4 ) is observed (Figure S1a‐d), which is typical for π ‐conjugated 1,2,3‐triazol‐1,4‐diyl‐fluoroionophores [11a–e] . The long‐wavelength CT bands of Zn1 , Zn2 , Zn3 and Zn4 show only a small shift in the presence of Zn 2+ (Figures S1a‐d), but the Zn 2+ complexation by the ionophore in Zn1 , Zn2 , Zn3 and Zn4 can be seen from the short‐wavelength CT transitions.…”

“…In a further study, they developed selective fluorescent probes for K + by using the highly K + /Na + selective ionophore the N ‐(o‐2‐methoxyethoxy)phenylaza‐18‐crown‐6 (cf. K1 and K2 , Scheme 2) [11a–e] and for Na + by using the highly Na + /K + selective ionophore the N ‐(o‐methoxyphenyl)aza‐15‐crown‐5 (cf. Na1 and Na2 , Scheme 2).…”

Photophysics of Acyl- and Ester-DBD Dyes: Quadrupole-Induced Solvent Relaxation Investigated by Transient Absorption Spectroscopy

“…Meanwhile, a range of applications of DBD dyes was developed. Thus, they were used as probes to study conformational changes in proteins, , in fluorescence-lifetime-based assays, , in various fluorescence resonance energy transfer pairs, − and in potassium selective probes and probes to selectively detect double-stranded DNA . Recently, we reported further development in the synthesis of DBD dyes, facilitating the adjustment of photophysical parameters to the requirements of an application …”