MoS2 decorated with Pd nanoparticles as a novel oxidase nanozyme for biothiol detection and cancer cell discrimination

The detection and discrimination of biothiols are of great significance for tumor cell identification and clinical diagnosis. Recently, nanozymes have been employed to construct biosensor arrays for the determination and differentiation of biothiols. However, most nanozymes currently used are peroxidase-like enzymes, which require highly toxic and unstable hydrogen peroxide (H 2 O 2 ) as a co-substrate to generate reactive oxygen species. Herein, MoS 2 @Pd nanozymes with good Pd dispersion were prepared by in situ growing Pd nanoparticles on MoS 2 nanosheets obtained via liquid-phase exfoliation. This strategy is green, mild, aqueous, and does not require additional reducing agents. Benefiting from the dispersion of Pd active sites and the electronic metal–support interaction, MoS 2 @Pd exhibits superior oxidase catalytic activity, which can effectively trigger the oxidation of the chromogenic substrate 3,3′,5,5′-tetramethylbenzidine (TMB) and induce changes in optical absorption. Based on the inhibitory effect of thiols on the chromogenic system, the constructed biosensor can be successfully applied for the sensitive analysis of common thiols. More importantly, the three absorption peaks generated by oxidazed TMB at 370 nm, 450 nm, and 652 nm can serve as three colorimetric channels. Through pattern recognition methods, good differentiation effects can be achieved for biothiols and their mixtures, and successful identification and differentiation of liver cancer cells have been realized. Therefore, MoS 2 @Pd nanozyme provide an easy and cost-effective method, offering new ideas for the construction of sensor arrays and the effective recognition of biothiols and cancer cells.