A "Three-in-One" AuNRs@ZIF-8/AuNPs Nanoplatform: Nanoenzyme-Mediated SERS-Colorimetric Bimodal Detection of Intracellular Glutathione and Photothermal Therapy.

Glutathione (GSH) serves as a core mediator in diverse life activities. Its abnormal expression or function is also closely linked to the pathogenesis of numerous human diseases. However, the current GSH detection generally has only diagnostic capabilities and is rarely linked to therapeutic functions, leading to a disconnect between basic detection and clinical intervention. Herein, we developed a AuNRs@ZIF-8/AuNPs core-shell nanocomposite as a "three-in-one" substrate, endowed with superior POD-like activity, strong SERS amplification performance, and mild photothermal properties. Its mimetic POD-like activity can facilitate the oxidation of colorless 3,3',5,5'-tetramethylbenzidine (TMB) to blue oxidized TMB (ox-TMB), generating a strong SERS signal. In the presence of GSH, this oxidation is inhibited, leading to color fading and diminished SERS signals. Based on the above characteristics, a versatile platform was developed for SERS-colorimetric dual-mode detection of GSH, with detection limits as low as 0.019 and 1.28 μM for SERS and colorimetric modes, respectively. Furthermore, the developed dual-modal biosensor has been successfully applied for the determination of intracellular GSH levels, providing a potent and straightforward tool for intracellular GSH analysis. Significantly, the experiments also showed this material possesses photothermal sterilization and tumor ablation effects, thereby endowing the nanocomposite with a "diagnosis-therapy integration" potential application. This study presents a promising example for precision detection and synergistic therapy.