Nanopore-Based Strategy for Sensing of Copper(II) Ion and Real-Time Monitoring of a Click Reaction.

A straightforward yet efficient, nanopore-based strategy that enables the sensitive detection of copper(II) ion (Cu2+) and real-time monitoring of a click reaction is provided. Two single-stranded DNAs (ssDNAs) are designed to act as the preprobes, one being modified with an azide and the other an alkyne. The presence of Cu2+ induces the ligation of two ssDNAs via click reaction, leading to the formation of a forked DNA which can quantitatively generate characteristic current signatures when interacts with α-hemolysin (α-HL) nanopore. The assay facilitates a highly selective and sensitive measurement of Cu2+ without the need for labels or signal amplification. More importantly, this nanopore platform exhibits excellent performance in real-time monitoring of a copper(I) ion (Cu+)-catalyzed click reaction at the single-molecule level, by recording the current signals of the forked DNA generated by click chemistry. The proposed strategy is believed to play an important role in both nanopore sensing and characterization of chemistry reactions, especially coupling reactions.