DNA-guided confined growth of bimetallic nanoclusters for constructing a multienzyme-integrated nanoplatform

Over the past decade, the study of DNA-templated metal nanoclusters (DNA-MNCs) has made rapid progress. It demonstrates broad application prospects in the fields of biosensing, medical diagnostics, and environmental monitoring. Despite the significant achievements of DNA-MNCs in optical properties, little study has been conducted on the catalytic properties of DNA-MNCs. We have successfully synthesized DNA-Au/Pt bimetallic NCs through a chemical reduction method, which exhibit excellent peroxidase-like (POD-like) activity. Due to the synergistic effect between the bimetals and an efficient electron transfer mechanism, their catalytic activity far surpasses that of monometallic NCs, and their affinity for hydrogen peroxide (H2O2) is even superior to horseradish peroxidase (HRP). By adjusting the template sequences and structures, we found that the catalytic activity of the four DNA homopolymer templates follows the trend: PolyC > PolyA > PolyG > PolyT, indicating that the C base has the strongest affinity for Au and Pt ions. For the same nucleation sequence, the catalytic activity of DNA-Au/Pt nanozymes is closely related to the length and structure of the DNA template sequence used. Based on these findings, combined with the cleavage action of DNAzymes to trigger the transformation of DNA structure, we have proposed a biosensing method for detecting miRNA. Besides, The DNA-Au/Pt nanozyme possesses dual enzyme-like activities of catalase (CAT) and laccase (LAC). Based on the dual-enzyme cascade catalytic system, it can efficiently degrade the organic pollutant malachite green (MG) into less toxic products. This research offers valuable insights into the synthesis of DNA templated nanozymes, and it highlights the potential for optimizing their performance by modulating the DNA sequences. More importantly, this research provides new insights for the design and application of multienzyme activities and multifunctional applications nanozymes in the future.