An off–on fluorescent probe based on N,S-GQDs/CoOOH nanocomplexes in vivo analysis of ascorbic acid

Abstract

Detecting ascorbate imbalances is crucial for timely disease diagnosis and sample monitoring across various conditions. In this study, we synthesized N,S-GQDs and employed the fluorescence quenching effect of CoOOH nanosheets through resonance energy transfer (FRET) to visually detect changes in ascorbate levels. Upon the addition of ascorbic acid (AA), the reduction reaction with CoOOH induced fluorescence recovery in N,S-GQDs. Our findings demonstrate that the synthesized N,S-GQDs/CoOOH nanocomplexes provide a reliable probe for fluorescence-based detection of ascorbic acid within a linear range of 2–82 μM, with a detection limit of 48.3 nM. Additionally, quantitative determination of ascorbic acid in blood and orange juice samples was successfully achieved using the N,S-GQDs/CoOOH, with good recovery rates. Importantly, confocal fluorescence imaging experiments conducted on MCF-7 cells and zebrafish confirmed that the synthetic N,S-GQDs/CoOOH can effectively visualize the overexpression of ascorbic acid in vivo.