An endoplasmic reticulum-targeted and near-infrared fluorescent probe for determining hydrogen polysulfides derived...

Hydrogen polysulfides (H₂S_n, n > 1) was the oxidized form of H₂S and plays significant roles in physiological and pathological processes. Abnormal levels of H₂S_n is associated with a series of physiological diseases. The endoplasmic reticulum-targetable fluorescent probes are rare for determining H₂S_n. Therefore, quantitative detection of H₂S_n levels in the endoplasmic reticulum is extremely crucial. In this study, a naphthalimide-based near-infrared fluorescent probe was constructed for detecting H₂S_n in the endoplasmic reticulum. 2-Fluoro-5-nitrobenzoate was chose as the H₂S_n sensing element. Before the addition of H₂S_n, the probe exhibited very weakly fluorescence at 700 nm. After adding H₂S_n, the probe demonstrated intense red fluorescence at 700 nm. The probe responded rapidly and exhibited excellent selectivity and sensitivity. And the probe displayed negligible cytotoxicity and had been successfully utilized for near-infrared imaging of H₂S_n within the endoplasmic reticulum of A549 cells. Additionally, the probe was also employed for imaging H₂S_n in zebrafish and exhibited satisfied results.