A universal tunable nanofluidic diode via photoresponsive host\u2013guest interactions

Pei Liu,Xiang-Yu Kong,Yuanyuan Zhao,Linsen Yang,Lei Jiang,Pei Li,Zhen Zhang,Liping Wen,Ganhua Xie,Congcong Zhu

doi:10.1038/s41427-018-0079-5

Abstract

Inspired by biological ion channels, scientists have fabricated various artificial nanosystems. However, nanofluidic diode systems with replaceable functional groups are rarely reported. In this work, we demonstrated a universal tunable nanofluidic diode based on a conical polyimide nanochannel. Using host–guest interactions between β-cyclodextrin and azobenzene, bidirectional nanofluidic diodes were prepared, and the degree of rectification could be adjusted with high precision by tuning the pH conditions. This work provides a novel approach to create a nanofluidic platform with replaceable surface functional groups, which has great potential in fields such as photosensitive nanofluidic devices, drug transport and release, and nanofluidic logic devices.

Highlights

We demonstrated a pH-regulated bidirectional nanofluidic diode via photoresponsive host–guest interactions based on a conical polyimide (PI) nanochannel
By immobilizing β-cyclodextrin as the “host” and preparing various functionalized Azo-end groups as “guests”, a universal tunable system that returns to the original state under different light stimuli can be realized (Scheme 1).[38]
The ion transport property of the nanochannel before and after modification with β-CDs was characterized by transmembrane ion current measurements in 0.1 M KCl solutions of different pH values

Summary

Introduction

Biological ion channels[1,2,3] embedded within cell membranes play a significant role in exchanging material, transporting ions, and transforming energy with the extracellular world.[4,5,6] Inspired by their genius designs and outstanding properties, scientists have developed various artificial nanosystems[7,8,9,10] that are capable of sensing or separating a diverse variety of ions in aqueous solutions.[11,12] Recent advances in smart nanofluidic devices in chemistry, materials science, and nanotechnology have gained increasing attention, and nanofluidic diodes, in particular, have evolved quickly.[13,14,15,16,17] One of the main characteristics of ion transport in these diode-like nanosystems is the ion-rectifying effect.[13,14,17,18] Like diodes in electronic devices, nanofluidic diodes exhibit ion unidirectional transport behavior owing to several factors, the main of which is the asymmetric distribution of surfaceIn this work, we demonstrated a pH-regulated bidirectional nanofluidic diode via photoresponsive host–guest interactions based on a conical polyimide (PI) nanochannel. Biological ion channels[1,2,3] embedded within cell membranes play a significant role in exchanging material, transporting ions, and transforming energy with the extracellular world.[4,5,6] Inspired by their genius designs and outstanding properties, scientists have developed various artificial nanosystems[7,8,9,10] that are capable of sensing or separating a diverse variety of ions in aqueous solutions.[11,12] Recent advances in smart nanofluidic devices in chemistry, materials science, and nanotechnology have gained increasing attention, and nanofluidic diodes, in particular, have evolved quickly.[13,14,15,16,17] One of the main characteristics of ion transport in these diode-like nanosystems is the ion-rectifying effect.[13,14,17,18] Like diodes in electronic devices, nanofluidic diodes exhibit ion unidirectional transport behavior owing to several factors, the main of which is the asymmetric distribution of surface.

Methods

Results

Conclusion