Facile preparation of Ru@V2O4 nanowires exhibiting excellent tetra-enzyme mimetic activities for sensitive colorimetric H2O2 and cysteine sensing

In the last decades, nanozymes have drawn significant attention because of their higher stability and lower preparation cost than natural enzymes. In this report, the novel Ru@V 2 O 4 nanocomposite with multi-enzyme-like activities has been synthesized via one-step hydrothermal method and simple stirring. It was proved that the prepared Ru@V 2 O 4 nanowires presented magnificent tetra-enzyme-like activities, comprising oxidase-like (OD-like), peroxidase-like (POD-like), catalase-like (CAT-like) and superoxide dismutase-like (SOD-like) activity. Firstly, the kinetic investigation validated the OD and POD-mimics behaviors of Ru@V 2 O 4 nanowires, which were in conformity with the Michaelis-Menten kinetics. Then a bifunctional colorimetric sensing platform was constructed for the sensitive detection of H 2 O 2 and cysteine (Cys) on the basis of POD-like and OD-like enzyme activities of Ru@V 2 O 4 nanowires. H 2 O 2 could be detected by Ru@V 2 O 4 nanowires over a range of 1–500 μM and the response limit was 0.788 μM. Under optimal conditions, the degree of discoloration was linearly proportional to the concentration of Cys in the range of 3–50 μM with a low detect limit of 0.139 μM. Besides, Ru@V 2 O 4 nanowires can detect H 2 O 2 in water samples and Cys in serum samples. Therefore, this research significantly expands the application of the tetra-enzyme mimetic Ru@V 2 O 4 nanowires in the fields of biosensing, biocatalysis, environmental monitoring and medical diagnosis.