Dual-mode colorimetric/photoelectrochemical sensing platform derived from the decomposition of CuHPT for glutathione detection

The development of integrated dual signal outputs for the reliable and accurate determination of glutathione (GSH) is highly significant for its key role in physiological processes. Herein, a colorimetric/photoelectrochemical (PEC) dual-mode sensing platform was constructed based on the GSH-triggered decomposition of a copper-organic framework (CuHPT). A hollow nanostructured type-II heterojunction of CoS/In-CdS was synthesized using an imidazolate framework (ZIF-67) as a template. CuHPT was decomposed in the presence of GSH to form catechol ligands and Cu⁺, enabling dual-mode sensing. An ion exchange reaction between the produced Cu⁺ and Cd²⁺ of CoS/In-CdS resulted in the formation of Cu₂S, causing a decrease in the photocurrent and the sensitive detection of GSH. Cu⁺ catalyzed H₂O₂ to produce ˙OH <i>via</i> a Fenton-like reaction, achieving colorimetric sensing. The proposed dual-mode sensor based on the target-triggered decomposition of CuHPT exhibited linear responses for colorimetric and PEC sensing of GSH in the range of 0.05-1.20 mM and 0.5-800 μM with the limit of detections (LODs) of 18 μM and 0.11 μM, respectively. The reliable determination of GSH in human serum provides a new possibility for the application of the present dual-mode sensor in clinical assays.