@article{SchwarzeRiemerEidneretal.2015,
  author    = {Schwarze, Thomas and Riemer, Janine and Eidner, Sascha and Holdt, Hans-J{\"u}rgen},
  title     = {A Highly K+-Selective Two-Photon Fluorescent Probe},
  series = {Chemistry - a European journal},
  volume    = {21},
  journal   = {Chemistry - a European journal},
  number    = {32},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {0947-6539},
  doi       = {10.1002/chem.201501473},
  pages     = {11306 -- 11310},
  year      = {2015},
  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 (K-d) values in Na+-free solutions (K-d(OP)=(28 +/- 5) mM and K-d(TP)=(36 +/- 6) mM) and in combined K+/Na+ solutions (K-d(OP)=(38 +/- 8) mM and K-d(TP)=(46 +/- 25) mM) reflecting the high K+/Na+ selectivity of the fluorescent probe. The TP absorption cross-section (sigma(2PA)) of the TPEF probe+160 mMK(+) is 26 GM at 860 nm. Therefore, the TPEF probe is a suitable tool for the in vitro determination of K+.},
  language  = {en}
}