Fast fluorescence dynamics in non-ratiometric calcium indicators
  A fluorescence decay of high-affinity non-ratiometric Ca2+ indicator Oregon Green BAPTA-1 (OGB-1) is analyzed with unprecedented temporal resolution in the two-photon excitation regime. A triple exponential decay is shown to best fit the fluorescence dynamics of OGB-1. We provide a new model for accurate measurements of the free Ca2+ concentration and dissociation constants of non-ratiometric calcium indicators. 
M. Gersbach, D. L. Boiko, C. Niclass, C. Petersen and E. Charbon