A novel fluorescent probe visualization and identification of sulfite in acute liver injury and knee osteoarthritis

This study presents a novel near-infrared fluorescent probe (HD) specifically engineered for real-time tracking of sulfite (SO₃²⁻) dynamics. Significantly, this work constitutes the first documented application of an SO₃^2--activated molecular tool in acute liver injury (ALI) and knee osteoarthritis (KOA) models. The probe demonstrates a distinct emission response at 720 nm upon 670 nm excitation following interaction with SO₃²⁻, maintaining exceptional selectivity across broad pH ranges. Levulinate was strategically incorporated as the recognition moiety to ensure precise and reproducible detection. Comparative analysis reveals HD's superior optical performance relative to existing sulfite probes, characterized by an exceptional response magnitude (∼300-fold enhancement) and high sensitivity. The probe successfully quantified intracellular SO₃²⁻ fluctuations across diverse cell types. Notably, HD achieved in situ visualization of SO₃²⁻ variations in both CCl₄ and APAP-induced ALI models. Through advanced in vivo and depth-penetration fluorescence imaging, the probe dynamically mapped SO₃²⁻ concentration gradients during pathological progression from hepatic injury to carcinogenesis, concurrently monitoring therapeutic responses. In addition, HD could monitor the level of SO₃²⁻ in KOA patients. This technological advancement enables precise spatial-temporal detection of SO₃²⁻ in hepatotoxic and KOA environments, offering a robust platform for preclinical diagnostics and translational medical research.