title: A Highly K(+)-Selective Two-Photon Fluorescent Probe.
abstract: A highly K(+)-selective two-photon fluorescent probe for the in vitro monitoring of physiological K(+) levels in the range of 1-100 mM is reported. The two-photon excited fluorescence (TPEF) probe shows a fluorescence enhancement (FE) by a factor of about three in the presence of 160 mM K(+), independently of one-photon (OP, 430 nm) or two-photon (TP, 860 nm) excitation and comparable K(+)-induced FEs in the presence of competitive Na(+) ions. The estimated dissociation constant (Kd ) values in Na(+)-free solutions (Kd (OP) =(28±5) mM and Kd (TP)=(36±6) mM) and in combined K(+)/Na(+) solutions (Kd (OP) =(38±8) mM and Kd (TP)=(46±25) mM) reflecting the high K(+)/Na(+) selectivity of the fluorescent probe. The TP absorption cross-section (σ2PA ) of the TPEF probe+160 mM K(+) is 26 GM at 860 nm. Therefore, the TPEF probe is a suitable tool for the in vitro determination of K(+).
authors.affiliation: Institut für Chemie, Anorganische Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Golm (Germany).
authors.forename: Thomas
authors.initials: T
authors.lastname: Schwarze
authors.affiliation: Institut für Chemie, Anorganische Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Golm (Germany).
authors.forename: Janine
authors.initials: J
authors.lastname: Riemer
authors.affiliation: Institut für Chemie, Physikalische Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Golm (Germany).
authors.forename: Sascha
authors.initials: S
authors.lastname: Eidner
authors.affiliation: Institut für Chemie, Anorganische Chemie, Universität Potsdam, Karl-Liebknecht-Str. 24-25, 14476 Golm (Germany). holdt@uni-potsdam.de.
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Holdt
keywords: click chemistry; fluorescence; fluorescent probes; potassium; two-photon