Reversible FRET Fluorescent Probe for Ratiometric Tracking of Endogenous Fe³⁺ in Ferroptosis

Abstract

A reversible fluorescent probe <b>DRhFe</b> is devised by linking spirolactam rhodamine and dansylamide through an Fe³⁺ ionophore <i>N</i>²-hydroxyethyldiethylenetriamine, where Fe³⁺ chelation generating rhodamine B can switch intramolecular fluorescence resonance energy transfer for ratiometric Fe³⁺ sensing. Probe <b>DRhFe</b> exhibits an Fe³⁺-specific emission shift from 483 to 576 nm, and this ratiometric response has been successfully applied to monitor labile Fe³⁺ fluctuations in cells undergoing ferroptosis.