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

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