A Switchable Two‐Photon Membrane Tracer Capable of Imaging Membrane‐Associated Protein Tyrosine Phosphatase Activities

When I look into your cells: A two-photon dye (Flu7) was developed (see scheme), which strongly fluoresces only upon selective binding to the plasma membrane of mammalian cells. Upon addition of a UV- and phosphatase-controlled quencher (Q12), the system exhibits ON/OFF/ON fluorescence switching and can be used to image membrane-associated receptor-like protein tyrosine phosphatase (RPTP) activity.