Label-free electrochemical biosensor based on GR5 DNAzyme/Ti3C2Tx Mxenes for Pb2+ detection

The interactions between nucleic acids and nanomaterials have been often utilized to design the electrochemical biosensor due to easy preparation, adsorptive tunability and high sensitivity. In this study, we have prepared a new electrochemical biosensor for Pb2+ detection based on GR5 DNAzyme/Ti3C2Tx Mxenes modified glassy carbon electrode (GR5 DNAzyme/Ti3C2Tx Mxenes-GCE). GR5 DNAzyme is an RNA-cleavage-type DNAzyme that shows high specificity towards Pb2+. With the presence of Pb2+, the cleavage of GR5 DNAzyme is activated at a ribo-adenine (rA) site in the substrate stranded DNA, leading to the unwinding of double-helix structure. This can enhance the adsorptive property of Ti3C2Tx Mxenes toward GR5 DNAzyme, which favors the ion intercalation into the Ti3C2Tx Mxenes and induces the increase of oxidation peak current. Therefore, we have successfully applied GR5 DNAzyme/Ti3C2Tx Mxenes-GCE to detect Pb2+ with a linear range from 0.5 to 32 nM and a detection limit of 0.1 nM. This electrochemical biosensor is simple, sensitive and selective for Pb2+ determination that it should find some potential applications in food safety inspection and environmental monitoring.

Automated summary

In this study, a new electrochemical biosensor for Pb2+ detection was designed based on the interactions between nucleic acids and nanomaterials. The biosensor showed easy preparation, adsorptive tunability, and high sensitivity, making it suitable for potential applications in food safety inspection and environmental monitoring.