Nanopore sensor for copper ion detection using a polyamine decorated β-cyclodextrin as the recognition element

Abstract

A novel and simple nanopore sensing method has been developed for the detection of CuII ions using polyamine decorated cyclodextrin as the recognition element. The strong binding affinity between CuII and the amino groups of cyclodextrin inside an α-hemolysin pore causes the new current blockade events. The event frequency is linear for concentrations of CuII in the range 0.08-20 μM. The detection limit is as low as 12 nM. More significantly, the sensing system is highly specific for CuII and does not respond to other metal ions with concentrations up to 10 fold that of CuII. The applicability of this sensor has also been verified by the analysis of CuII ions in running water, suggesting the potential application of this sensing system.