Triggering cascade detection of rutin and Al3+ via 3D ratiometric fluorescent probe through lateral flow assay installation based on dual-emission carbon dots

The persistent existence of flavonoid medications and hazardous ion residues continue to be a concern. Herein, a novel 3D cascade nitrogen-doped carbon dots (N-CDs) based sensing platform for specific detection of rutin and Al³⁺ has been developed, utilizing 3,3-diaminobenzidine and catechol as precursors through solvothermal way. The N-CDs exhibit a blue emission peak at 410 nm and a green emission peak at 518 nm. Upon the introduction of rutin, the signal value at 410 nm is significantly reduced by strong inner filter effect (IFE) and weak fluorescence resonance energy transfer (FRET) while the signal value at 518 nm is marginally quenched by weak IFE. Then, with the addition of Al³⁺, the rutin-Al³⁺ complex formed causes the decrease of the signal value at 410 nm by strong FRET and weak IFE while the signal value at 518 nm is decreased by strong IFE. Correspondingly, based on the 3D fluorescence excitation-emission matrix, a novel cascade fluorescent sensor is designed, which shows a good linear relationship with the concentration of rutin and Al³⁺ within the ranges 0.059–35 μM and 0.098–20 μM, featuring limits of detection (LOD) around 59 nM and 98 nM, respectively. In addition, a fluorescence sensing platform based on the lateral flow assay installation has been developed for portable and on-site detection of rutin and Al³⁺. This work not only broadens the application scope of CDs in sensing fields but also offers a highly effective approach for creating a superior fluorescent sensor to detect rutin and Al³⁺, ultimately enhancing capabilities in environmental monitoring.

Graphical abstract