Fluorometric detection of quinolones via AIE and FRET with terbium-doped carbon dots and copper nanoclusters

Terbium and nitrogen co-doped carbon dots (Tb@N-CDs), combined with α-lipoic acid-functionalized copper nanoclusters (LA@CuNCs), were proposed for the ratiometric detection of quinolone (QA) antibiotics. In this system, Tb@N-CDs facilitate the aggregation of LA@CuNCs, enhancing its fluorescence emission at 670 nm via aggregation-induced emission enhancement (AIEE). Meanwhile, the fluorescence emission of Tb@N-CDs at 460 nm diminishes due to Förster resonance energy transfer (FRET). Upon the introduction of QA, the binding between Tb3+ ions and N-CDs weakens, disrupting both AIEE and FRET processes. This disruption results in a reduction in fluorescence emission at 670 nm and a concurrent increase at 460 nm. The fluorescence response ratio (F460/F670) increases with higher concentrations of ciprofloxacin (CFX), demonstrating a linear range from 0.008 to 120 μmol L−1 and LOD of 1.6 nmol L−1. The method successfully detected CFX in milk and urine samples, achieving recoveries between 97.7 % and 103.8 %, RSD of less than 3.79 %. •A novel fluorescent hybrid was proposed for sensing of quinolones.•The fluorescent probe is LA@CuNCs/Tb@N-CDs.•Tb@N-CDs enhanced the fluorescence of LA@CuNCs via AIE effect.•The fluorescence emission of Tb@N-CDs was decreased due to FRET.•Addition of quinolones hindered the AIE and FRET between Tb@N-CDs and LA@CuNCs.