Gated nanochannels extensively exist in biological system, functionalized as reporters to specific external stimuli or transporters of signaling messengers and molecules, such as voltage gated ion channels and ligand gated channels.  

In recent years, based on micro-nano engineering and chemical modification, studies on gated nanochannels controlled by light, temperature, electric field and metal ions have been reported. Compared with other control factors, magnetic field, which has high penetrability, has a significant advantage in non-contact control of insulators, conductive solids, liquid, human tissue and other materials. 

Lately, researchers at the Institute of Modern Physics (IMP) of the Chinese Academic of Sciences demonstrated a novel magnetically gated polyethylene terephthalate (PET) nanochannel with magnetic sensors inside for the first time. 

The researchers have successfully fabricated a new kind of fast-response magnetic-controlled nanochannel by applying techniques of single ion hit and ion track etching of Lanzhou Interdisciplinary Heavy Ion Microbeam (LIHIM). 

In this work, DNA single strands and magnetic nanoparticles were successively modified onto the inner surface of the nanochannel by dehydration condensation, forming a kind of sandwich-like structure. The nanochannel was switched within sub-second between ON/OFF state when the permanent magnet with the magnetic field strength of 220 mT was placed at the mouth/tip side of the nanochannel, and the current ratio was about 18.4.  

This kind of nanochannel not only has unique advantages in superficial drug-delivery and non-contact control in nanofluidic applications, but also provides a new insight into the mechanism of pigeons' orientation by using the geomagnetic field. 

The work was published in ChemNanomat and selected as a cover feature. The study was supported by the National Natural Science Foundation of China. 

Figure 1. The magnetically gated PET nanochannel and its repetitive ON/OFF under the control of magnetic field. (Image by IMP) 

Figure 2. The work was selected as the cover feature of Volume 7 of the journal in 2020. (Image by ChemNanomat)