Highly Robust Nanopore-Based Dual-Signal-Output Ion Detection System for Achieving Three Successive Calibration Curves

In recent years, artificial stimuli-responsive bioinspired nanopores have attracted a lot of attention due to their unique property of confined spaces and flexibility in terms of shapes and sizes. Most of the nanopore systems demonstrated their transmembrane properties and applications in target detections. However, almost all of the nanopores can be used only once due to either the irreversible reactions between targets and probes or the plugged nanopores not easily being unplugged again. In this work, we propose a dual-signal-output nanopore system that could detect the cations (Hg2+) inducing the plugged nanopores. The detection system is highly recoverable by the anions (S2-) inducing the unplugged nanopores. More importantly, as far as we know, it is seldom reported for the same nanopores to achieve successive calibration curves for three times by subsequent reversible plug unplug processes, which strongly demonstrates the high robustness of this novel nanopore-detection system. In addition, unlike monitoring the plug-unplug phenomena by only one type of signal, we combined the ionic current signal with the fluorescence output and could directly observe that the change of ionic current does in fact correspond to the plug unplug of the nanopores by the target stimuli.