A turn-on AIE dual-channel fluorescent probe for sensing Cr³⁺/ClO^- and application in cell imaging

A Cr³⁺/ClO^--enhanced fluorescent probe, DNS (5-(dimethylamino)-N'-(2-hydroxy-4,6-dimethoxybenzylidene)-naphthalene-1-sulfonyl hydrazide), with aggregation-induced emission (AIE) properties was synthesized using dansylhydrazide and 4,6-dimethoxysalicylaldehyde as starting materials. The probe rapidly and selectively detects Cr³⁺ and ClO^- in a solvent system of H₂O/DMSO (2:8). Upon binding with Cr³⁺/ClO^-, the probe exhibits a significant fluorescence enhancement, with minimal interference from other ions. The detection limits (LOD) were determined to be 5.36 × 10^-7 mol/L for Cr³⁺ and 3.65 × 10^-7 mol/L for ClO^-. The binding mechanisms of DNS with Cr³⁺/ClO^- were investigated through Job's plot, 1H NMR titration, and mass spectrometry. Furthermore, the probe's low cytotoxicity and biocompatibility suggest its potential for detecting exogenous Cr³⁺/ClO^- and endogenous ClO^- in living cells. DNS shows promise for real-time detection and bioimaging applications.