Bioinspired Multivalent Ion Responsive Nanopore with Ultrahigh Ion Current Rectification

Ion transport in bionanopores is closely related to biological processes and can be regulated by various external stimulations. Multivalent ion as one of the stimulators shows a great ability in tuning the ion transport properties, while the mechanism is yet unclear. Here, inspired by this multivalent ion involved process, we propose a multivalent ion responsive symmetric hourglass polycarbonate nanopore. Addition of multivalent ion triggers formation of an abrupt bipolar junction inside the nanopore, and an ultrahigh ion current rectification ratio higher than 650 can be achieved. The ion transport property can be reversibly and significantly regulated via the reversible adsorption/desorption of multivalent ions on nanopore surface. This study provides the fundamentals to an understanding of the biological process and proposes an effective strategy to build smart nanofluidic devices.