Cobalt oxyhydroxide nanoflakes integrating with 7-amino-4-methylcoumarin for sensitive detection of glutathione

Glutathione (GSH), an essential biothiol, plays a critical role in reversible redox reactions, cellular signaling, detoxification, and metabolism. Fluctuations in GSH levels are closely linked to serious health conditions, underscoring the significance of monitoring its concentration. Fluorescence-based sensing with nanomaterials offers a promising strategy for rapid GSH detection. In this work, we developed a fluorescent probe integrating 7-amino-4-methylcoumarin (AMC) and cobalt oxyhydroxide nanoflakes (CoOOH NFs) for GSH detection through a combined internal-filter effect and static quenching mechanism. The introduction of GSH triggered a redox reaction that degraded CoOOH NFs, suppressing their quenching effect and restoring AMC fluorescence, which enabled GSH quantification through fluorescence recovery. The probe detected GSH in the range of 20–200 μM with a detection limit of 0.13 μM. It was successfully applied to determine GSH in human serum, and the results showed excellent agreement with those measured by a commercial GSH detection kit based on the use of Ellman's reagent.