A novel fluorescent sensing platform for glutathione based on Förster resonance energy transfer and aggregation-induced emission

Glutathione (GSH) plays essential roles in anti-oxidation and detoxification within the human body. An imbalance in its concentration can lead to serious health conditions. Therefore, accurate monitoring of GSH is critical for maintaining human health. In this study, we present a novel GSH detection method that enhances the fluorescence of α-lipoic acid-functionalized gold nanoclusters (LA@Au NCs) through aggregation induced by zinc and nitrogen co-doped carbon dots (Zn@N-CDs). Additionally, the fluorescence of Zn@N-CDs (donor) decreases upon adding LA@Au NCs (acceptor), indicating Förster resonance energy transfer (FRET) between them. In the presence of GSH, complexation with Zn²⁺ on the N-CD surface disrupts both the aggregation induced emission (AIE) and FRET mechanisms. This disruption leads to the restoration of N-CD fluorescence while simultaneously quenching the fluorescence of LA@Au NCs. Under optimized conditions, the fluorescence response ratio (F₄₆₅/F₆₇₀) is directly proportional to the concentration of GSH within a linear dynamic range of 0.1-90 µM, with a detection limit (S/N = 3) of 0.03 µM. This novel combination paves the way for the development of fluorescent probes for detecting various molecules and biomolecules.