Pd@Pt nanoparticles: Trienzyme catalytic mechanisms, surface-interface effect with DNA and application in biosensing

As a new field, there are still many unknowns and challenges in the study of nanozymes, such as the mechanism of the reaction catalyzed by nanozymes and the precise control of the catalytic activity of nanozymes. We found that Pd@Pt nanoparticles (NPs) have trienzyme mimetic activity, including peroxidase-like, catalase-like, and oxidase-like activity. More importantly, we observed that the catalytic performance can be modulated by DNA. After systematic studies, the potential mechanisms of DNA modulation of nanozymes were through local coordination, van der Waals forces, and hydrophobic forces, constructing an interface modulation in the Pd@Pt NP enzyme-like system. Based on the surface-interface effect between DNA and Pd@Pt NP nanozymes, a colorimetric sensor was constructed for rapid, accurate and selective analysis of Salmonella by using a specific aptamer. After optimization, the limit of detection was calculated to be similar to 58 CFU mL(-1). These results indicated that the catalytic activity of Pd@Pt NP nanozymes can be modulated by DNA, and the surface-interface effect has potential in the application of analytical assays.

Automated summary

DNA can modulate the catalytic activity of Pd@Pt NP nanozymes, providing a new approach for the construction of rapid, accurate and selective analysis sensors.