Dual-functional fluorescence probe for detecting hydroxylamine and viscosity in living cells and zebrafish

Hydroxylamine is vital in biological processes, acting as a significant byproduct of cellular metabolism and a crucial intermediate in the transformation of l-arginine to nitric oxide (NO) and nitroxyl (HNO). This study presents the design and synthesis of a novel fluorescent probe, CSO-CY, which is constructed from a rigid planar thienocoumarin fluorophore connected to a cyanoacetate moiety through a carbon–carbon double bond. The probe interacts with hydroxylamine to produce an oxime derivative during hydroxylamine detection, leading to a reduction in fluorescence intensity at 653 nm and an enhancement at 490 nm. Moreover, fluorescence intensity at 466 nm incrementally rises in high-viscosity environments. Overall, CSO-CY demonstrates significant selectivity, a fast response time (25 s), and remarkable sensitivity (detection limit: 142 nM) in PBS buffer across an extensive pH range (6–11) towards sensing hydroxylamine, rendering it highly appropriate for intricate physiological conditions. The probe has been effectively utilized for the detection of hydroxylamine in living cells and zebrafish. These findings indicate that CSO-CY is a promising chemosensor for monitoring hydroxylamine dynamics and viscosity in biological systems, underscoring its considerable practical potential.