Highly sensitive and rapid colorimetric sensing platform based on water-soluble WO_x quantum dots with intrinsic peroxidase-like activity

This report outlines a rapid and highly sensitive colorimetric sensing platform based on a novel water-soluble WO_x quantum dots (QDs) as enzymatic mimics. The WO_x QDs, synthesized by a green hydrothermal method, were proven to possess excellent intrinsic peroxidase-like activity. The peroxidase substrate, 2, 2′-azinobis (3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt (ABTS) could be catalyzed oxidation by WO_x QDs quickly in the present of H₂O₂ to form a green color. Due to its excellent properties such as excellent water-solublity, good biocompatibility, easy preparation, and high stability, the proposed system showed typical Michaelis-Menten kinetics and high affinity for ABTS and H₂O₂, indicating WO_x QDs can be used as satisfactory peroxidase mimics. Together with the fast detection process, WO_x QDs-based colorimetric sensing system provided a facile, sensitive, and accurate method for the determination of H₂O₂ and glucose. The real glucose samples in human serum samples were detected with satisfying results. The proposed sensing platform not only expands the applications of WO_x and WO_x QDs-based nanocomposites, but also provides an alternative technique for biological, biomedical and environmental sample assay. - Highlights: • Water-soluble WO_x QDs possess the excellent peroxidase-like activity. • Its peroxidase-like activity was studied by catalyzing the oxidation of ABTS with H₂O₂. • A sensitive and rapid colorimetric method for H₂O₂ and glucose determination was developed. • This colorimetric sensing platform can be easily adapted to measure other physiologically important compounds. • This work can facilitate the utilization of peroxidase mimics in various fields.