# Metal surface-triggered DNAzyme catalysis for efficient DNA cleavage

## TL;DR

This paper shows that metal surfaces can activate DNAzymes at solid-liquid interfaces, enabling DNA cleavage without dissolved metal ions.

## Contribution

The discovery that metal surfaces directly activate DNAzymes in heterogeneous systems is a novel extension of DNAzyme catalysis.

## Key findings

- PL DNAzyme is activated on copper, vanadium, and tantalum surfaces without dissolved metal ions.
- Superoxide anions generated from metal surfaces trigger DNA cleavage.
- The phenomenon is not limited to PL, as F-8, Ag10c, and I-R3 DNAzymes also show surface-mediated activation.

## Abstract

DNAzymes conventionally require dissolved metal ions for catalytic functions. Herein, we report that metal surfaces directly activate a self-cleaving DNAzyme (PL) at solid-liquid interfaces. PL exhibits activities on copper, vanadium and tantalum surfaces, within a minimal reaction system comprising only the metal surface, PL and double-distilled water. This interfacial activation is highly material-specific, showing complete absence of activity on plastics, glass or wood etc. Mechanistic studies reveal that dissolved oxygen could react with metal surfaces to generate superoxide anions, which serve as triggers for DNA-cleavage. The reaction shows modulatable characteristics, with inhibition by ethylenediaminetetraacetic acid, catalase, nitroblue tetrazolium and cytochrome c, versus enhancement by vitamin C, glutathione and catechol. Furthermore, metal surface-mediated activation was also observed in F-8, Ag10c and I-R3 DNAzymes, indicating that this phenomenon is not an isolated occurrence. This work establishes macroscopic metals as DNAzyme’s cofactors, extending DNAzyme catalysis beyond conventional homogeneous systems to heterogeneous interfacial environments.

DNAzymes rely on dissolved metal ions as cofactors for catalytic activity, however, the effects of metals in heterogeneous systems are not fully understood. Here, the authors demonstrate that metal surfaces can directly activate DNAzymes at solid-liquid interfaces, revealing a mechanism involving superoxide anions.