Dual channel detection of GSH based on AgNTs colorimetry and coupled plasmonic SERS.

Glutathione (GSH) is a crucial intracellular antioxidant that plays a central role in redox homeostasis, and its abnormal levels are closely associated with the pathogenesis of various diseases. Consequently, the development of rapid, sensitive, and reliable biosensing strategies for GSH quantification is of significant importance for clinical diagnostics and bioanalytical applications. Herein, we report a hierarchical dual-modal sensing platform that integrates Ag nanotriangles (AgNTs)-based colorimetry with MoS₂/Au nanoparticles (AuNPs)-enabled surface-enhanced Raman scattering (SERS) for robust GSH detection. The colorimetric modality operates via a "Cl--induced etching-GSH protection" mechanism, which triggers a distinct blue-to-yellow color transition, enabling rapid and naked-eye visual screening. In this module, the limit of detection (LOD) for colorimetric analysis is as low as 33 nM. For ultrasensitive quantitative detection, the SERS performance is driven by triple-resonance synergistic amplification at the MoS₂/AuNPs interface, arising from plasmonic electromagnetic "hot spots", the excitonic resonance of MoS₂, and plasmon-mediated charge-transfer interactions. This synergistic effect affords an ultralow SERS LOD of 10.78 nM under 633 nm excitation, with an impressive enhancement factor of 1.635 × 106 at 1332 cm-1. Furthermore, the proposed SERS substrate exhibits excellent signal uniformity (relative standard deviation, RSD < 9%), high selectivity, and outstanding long-term stability over 50 days. Its practical reliability is demonstrated through successful real-world sensing in fetal bovine serum and tomatoes samples. By integrating rapid visual readouts with quantitative analysis, this dual-modal strategy provides a versatile and sensitive biosensing platform for biothiols and other small-molecule biomarkers.