A near-infrared lysosomal probe for dynamic sulfur dioxide monitoring in inflammation

Inflammation is a complex physiological response involving various cellular and molecular events. Sulfur dioxide (SO₂), recognized as both an endogenous signaling molecule and anti-inflammatory agent, plays a crucial role in modulating inflammation and maintaining cellular homeostasis. To gain deeper insights into the dynamics of inflammation-related processes, real-time monitoring of SO₂ concentrations within cellular organelles is imperative. Here, we developed a near-infrared fluorescent probe, R2, equipped with lysosomal targeting features. R2 effectively monitors dynamic SO₂ concentration changes during inflammation. The fluorescence intensity at 703 nm of R2 shows a strong linear correlation with the concentration of SO₂, displaying a rapid response time to SO₂ within 10 s and maintaining excellent photostability. The successful application of R2 in elucidating dynamic SO₂ concentration changes in lysosomal during cellular and rat inflammatory processes underscores its significant potential as a tool for understanding the pathogenesis of inflammation-related diseases.