Sodium‐Ion‐Selective Two‐Photon Fluorescent Probe for In Vivo Imaging

Two photons are better than one: A two-photon probe (ANa1, see picture) shows strong two-photon fluorescence enhancement in response to Na+ and a dissociation constant (Kdi) of (26±2) mM in the cell. It can be easily loaded into the cells and can selectively detect intracellular free Na+ in live cells and living tissues at a depth of 100–200 μm for a long period of time. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents are peer-reviewed, but not copy-edited or typeset. They are made available as submitted by the authors. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.