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

The development of integrated dual signal outputs for reliable and accurate determination of glutathione (GSH) is highly significant for its key role in the 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 imidazolate framework (ZIF-67) as a template. CuHPT was decomposed in the presence of GSH to form catechol ligands and Cu+, enabling the dual-mode sensing. An ion exchange reaction between the produced Cu+ and Cd2+ of CoS/In-CdS resulted in the formation of Cu2S, causing the decrease of the photocurrent and the sensitive detection of GSH. Cu+ catalyzed H2O2 to produce ·OH via a Fenton-like reaction, achieving the 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 ranges 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 application of the present dual-mode sensor in clinical assay.