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A Pb2+ Ionic Gate with Enhanced Stability and Improved Sensitivity Based on a 4'-aminobenzo-18-crown-6 Modified Funnel-Shaped Nanochannel

Abstract

The existence of heavy ions in the external environment such as Pb2+ are potentially hazardous and highly toxic to human bodies. Inspired by the highly efficient ability of biological ion channels to recognize the metal ion, much effort has been devoted to investigate the biomimetic ionic gate based on the engineered solid-state conical nanopores/nanochannels. Howerver, the reported system generally behaves relatively poor functionlity and low stability due to the limited functional region. This article describes an ionic gate with enhanced stability and imporved sensitivity based on the emerging advanced funnel-shaped nanochannel system. The ionic gate is developed by anchoring the Pb2+ ion-responsive functional molecules, 4′-aminobenzo-18-crown-6 (4-AB18C6), onto the inner surface of a funnel-shaped polyethylene terephthalate (PET) nanochannel. The system can selectively recognize Pb2+ with an ultralow concentration to approximately 10-15 M and behaves excellent stability. The Pb2+ will form a positively charged complexes through specific association with the 4-AB18C6, which would screen the negative charge existed on the channel walls, resulting in a decreased ionic current and also an “OFF state”. Since the association ability of EDTA with Pb2+ is much stronger than that of 4-AB18C6, the nanochannel can also achieve reversible switching upon alternative addition of Pb2+ ion and EDTA. The switching behaviors of the system were reflected by the good reproducibility of the tunable rectifying effect. The stability of the conical and funnel-shaped nanochannels is also compared by current scanning under constant voltage. The results have shown that the stability of funnel-shaped nanochannel is much better than that of the conical nanochannel, which can be ascribed to its much longer critical region. Consequently, the funnel-shaped nanochannels with enhanced stability and improved sensitivity can potentially be applied in ion transportation, sensor, drug releasing and energy conversion.

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Publication details

The article was accepted on 13 Feb 2018 and first published on 21 Feb 2018


Article type: Paper
DOI: 10.1039/C8FD00025E
Citation: Faraday Discuss., 2018, Accepted Manuscript
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    A Pb2+ Ionic Gate with Enhanced Stability and Improved Sensitivity Based on a 4'-aminobenzo-18-crown-6 Modified Funnel-Shaped Nanochannel

    Y. Qian, Z. Zhang, W. Chen, L. Wen and L. Jiang, Faraday Discuss., 2018, Accepted Manuscript , DOI: 10.1039/C8FD00025E

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