A "signal-on" photoelectrochemical sensor based on hierarchical titanium dioxide nanowires/microflowers decorated graphite-like carbon nitride quantum dots for glutathione detection.

Glutathione (GSH) is a bioactive tripeptide with important physiological functions in animals, plants, and microorganisms. GSH participates in various biochemical reactions in vivo and is known for its antioxidant, anti-allergy, and detoxification properties. This study introduces an innovative photoelectrochemical (PEC) method for GSH detection, leveraging a fluorine-doped tin oxide (FTO) electrode enhanced by TiO nanoflowers and graphitic carbon nitride quantum dots (g-CNQDs). This design formed a type-II heterojunction, which facilitated efficient charge separation and transport. Furthermore, incorporating TiO nanoflowers increases the surface area, while adding g-CNQDs led to a narrowing of the semiconductor bandgap. The fabricated electrode exhibits highly attractive photo-electrocatalytic activity towards GSH detection in neutral media at a low potential bias. The developed PEC sensor demonstrates a wide linear range of 1.0 × 10 to 5 × 10 mol L, a low detection limit of 5.0 fmol L, and high sensitivity. These remarkable analytical characteristics highlight the potential of this PEC platform for sensitive and selective GSH detection in various biomedical and environmental applications.