Issue 25, 2023

Activity-enhanced DNAzyme for design of label-free copper(ii) biosensor


Metal ion-driven, DNA-cleaving DNAzymes are characterised by high selectivity and specificity. However, their use for metal ion sensing remains largely unexplored due to long reaction times and poor reaction yields relative to RNA-cleaving DNAzymes and other sensing strategies. Herein we present a study demonstrating a significant rate enhancement of a copper-selective DNA cleaving DNAzyme by both polydopamine (PDA) and gold (Au) nanoparticles (NPs). PDA NPs enhance the reaction through the production of hydrogen peroxide, while for AuNPs the enhancement is aided by the presence of citrate surface moeities, both of which drive the oxidative cleavage of the substrate. A 50-fold enhancement for PDA NPs makes the combination of PDA and DNAzyme suitable for a practical application as a sensitive biosensor for Cu(II) ions. Using DNAzyme deposition onto a gold electrode followed by Polydopamine Assisted DNA Immobilisation (PADI), we achieve a cost-effective, label-free and fast (within 15 min) electrochemical biosensor with a limit of detection of 180 nmol (11 ppm), thus opening a route for the rational design of a new generation of hybrid DNAzyme-based biosensors.

Graphical abstract: Activity-enhanced DNAzyme for design of label-free copper(ii) biosensor

Supplementary files

Article information

Article type
10 May 2023
04 Jun 2023
First published
14 Jun 2023
This article is Open Access
Creative Commons BY license

Nanoscale, 2023,15, 10776-10782

Activity-enhanced DNAzyme for design of label-free copper(II) biosensor

W. Etheridge, F. Brossard, S. Zheng, S. Moench, S. Pavagada, R. M. Owens and L. Fruk, Nanoscale, 2023, 15, 10776 DOI: 10.1039/D3NR02169F

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