A photostable luminescent iridium(III) complex probe for imaging endogenous mitochondrial sulfur dioxide in living cells

Abstract

Sulfur dioxide (SO₂) is an important signaling gas molecule, but its aberration is highly associated with inflammatory diseases and cancers. Luminescence probes for SO₂ have emerged as essential instruments for elucidating its biological roles and facilitating disease diagnosis, owing to their high sensitivity and capabilities for real-time detection. Nevertheless, the majority of current probes lack subcellular selectivity and suffer from limited photostability. In this work, we develop an Ir(III)-based luminescence probe (Ir3) for the rapid, real-time, and accurate detection of SO₂ in aqueous solution. This probe exhibits low cytotoxicity and provides exceptional imaging of mitochondrial SO₂ in living cells. We anticipate that this probe will serve as a foundational tool for the advancement of effective imaging technologies for SO₂, thereby enhancing the clinical and biomedical applications of Ir(III) complex-based detection probes.