Highly sensitive determination of glutathione with a colorimetric sensor based on bimetallic Pt-Cu nanorods as peroxidase mimetics.

Developing novel noble-metal nanozymes with well-defined morphology and high catalytic activity for sensitive and convenient detection of disease biomarkers like glutathione (GSH) is one of the most challenging hotspots nowadays. Here, taking H2PtCl6 and CuCl2·2H2O as precursors, cetyltrimethylammonium bromide as a structure-directing agent, and arginine as a reducing agent, bimetallic platinum-copper nanorods (Pt-Cu NRs) were synthesized by using a simple and effective one-pot method. Comprehensive characterization confirms that Pt-Cu NRs exhibited high alloyed structure and superior peroxidase-like activity compared with other shaped materials. Leveraging this performance, Pt-Cu NRs were then successfully employed to construct a highly sensitive colorimetric sensor for GSH. Interestingly, the principle is based on competitive depletion of hydroxy radicals (·OH) generated from the catalytic oxidation of H2O2 by Pt-Cu NRs nanozyme, where the competition occurs between GSH and the chromogenic substrate of 3,3',5,5'-tetramethylbenzidine (TMB). The colorimetric sensor showed good linear relationship between the absorbance response and GSH concentration in the range of 0.05∼50 μM and 50∼300 μM, with a detection limit of 10.5 nM. Notably, the proposed method possessed high selectivity and robust anti-interference capability, which has been successfully applied to the accurate determination of GSH in human serums from both healthy individuals and diseased patients, yielding results consistent with those obtained using commercial kits. These findings highlighted the sensor's significant application value in the fields of medical diagnosis and human health monitoring.