Rational Design of an Activatable Near‐Infrared Fluorogenic Platform for In Vivo Orthotopic Tumor Imaging and Resection

Rational and effective design of a universal near‐infrared (NIR) light‐absorbed platform employed to prepare diverse activatable NIR fluorogenic probes for in vivo imaging and the imaging‐guided tumor resection remains less exploited but highly meaningful. Herein, mandelic acid with a core structure of 4‐hydroxylbenzyl alcohol to link recognition unit, a fluorophore and a quencher was employed to prepare activatable probes. We exemplified ester as carboxylesterase (CE)‐recognized unit, ferrocene as quencher and phenothiazinium as NIR fluorophore to afford fluorogenic probes termed NBS‐Fe‐CE and NBS‐C‐Fe‐CE. These probes enabled the conversion toward CE with significant fluorescence increases and successfully discriminate CE activity in cells. NIR light enhances the tumor penetration and enable imaging‐guided orthotopic tumor resection. This specific case demonstrated that this platform can be effectively used to construct diverse NIR probes for imaging analytes in biological systems.