A label-free DNAzyme-based nanopore biosensor for highly sensitive and selective lead ion detection

Abstract

As the lead ion (Pb²⁺) can severely induce environmental pollution and harm human health, it is important to develop a simple, highly sensitive and selective sensor for Pb²⁺ detection. Herein, a label-free DNAzyme-based nanopore biosensor for the sensitive and selective quantification of Pb²⁺ has been developed. Pb²⁺ can trigger the cleavage of a hairpin substrate in the presence of DNAzyme and cause the increase of single-stranded DNA (ssDNA) products, which could generate current blockade signals distinguished from that of the hairpin substrate when tested with an α-hemolysin nanopore. The presence of Pb²⁺ can be detected at ∼3.48 nM or higher and the sensor is highly selective to Pb²⁺. Furthermore, the nanopore-based sensing strategy can be extended to other analytes which can trigger similar DNAzyme cleavage reactions.