TY  - JOUR
A1  - Schwarze, Thomas
A1  - Mertens, Monique
A1  - Mueller, Peter
A1  - Riemer, Janine
A1  - Wessig, Pablo
A1  - Holdt, Hans-Jürgen
T1  - Highly K+-Selective Fluorescent Probes for Lifetime Sensing of K+ in Living Cells
JF  - Chemistry - a European journal
N2  - The new K+-selective fluorescent probes 1 and 2 were obtained by Cu-I-catalyzed 1,3-dipolar azide alkyne cycloaddition (CuAAC) reactions of an alkyne-substituted [1,3]dioxolo[4,5-f][1,3]benzodioxole (DBD) ester fluorophore with azido-functionalized N-phenylaza-18-crown-6 ether and N-(o-isopropoxy) phenylaza-18-crown-6 ether, respectively. Probes 1 and 2 allow the detection of K+ in the presence of Na+ in water by fluorescence enhancement (2.2 for 1 at 2000mm K+ and 2.5 for 2 at 160mm K+). Fluorescence lifetime measurements in the absence and presence of K+ revealed bi-exponential decay kinetics with similar lifetimes, however with different proportions changing the averaged fluorescence decay times ((f(av))). For 1 a decrease of (f(av)) from 12.4 to 9.3ns and for 2 an increase from 17.8 to 21.8ns was observed. Variation of the substituent in ortho position of the aniline unit of the N-phenylaza-18-crown-6 host permits the modulation of the K-d value for a certain K+ concentration. For example, substitution of H in 1 by the isopropoxy group (2) decreased the K-d value from >300mm to 10mm. 2 was chosen for studying the efflux of K+ from human red blood cells (RBC). Upon addition of the Ca2+ ionophor ionomycin to a RBC suspension in a buffer containing Ca2+, the fluorescence of 2 slightly rose within 10min, however, after 120min a significant increase was observed.
KW  - electron transfer
KW  - fluorescence lifetime
KW  - fluorescent probes
KW  - living cells
KW  - potassium
Y1  - 2017
U6  - https://doi.org/10.1002/chem.201704368
SN  - 0947-6539
SN  - 1521-3765
VL  - 23
SP  - 17186
EP  - 17190
PB  - Wiley-VCH
CY  - Weinheim
ER  -