Gadolinium-Sensitive\nArtificial Nanochannel Membrane\nfor Information Encryption

Inspired from ion channels in the myelinated axon of Xenopus laevis found to be affected by gadolinium\non axonal currents, we present a solid nanochannel membrane sensitive\nto gadolinium (Gd<sup>3+</sup>), which can be achieved via the use\nof the macrocyclic triacetic acid derivative in the host–guest\nchemistry approach. The macrocyclic nanochannel has good responsiveness\ntoward Gd<sup>3+</sup>, even at the nanomolar concentration level,\nevidenced by discernible changes in rectification, ionic conductance,\nand XPS analyses. Notably, the Gd<sup>3+</sup>-sensitive nanochannel\nmembrane can be switched by the addition of a diethylenetriaminepentaacetic\nacid (DTPA) derivative. Further studies have indicated that the gated\nbehavior of Gd<sup>3+</sup> in the nanochannel can be attributed to\nthe strong binding strength between DO3A and Gd<sup>3+</sup>, which\ninduces a surface charge reversal within the nanochannel. The mechanism\nhas been confirmed through several experimental techniques, including\nisothermal titration calorimetry (ITC) experiments, fluorescence titration\nexperiments, and finite element analysis. Based on its Gd<sup>3+</sup> responsiveness of the constructed ion channel, we successfully developed\nan advanced multilevel information encryption application of the artificial\nsolid nanochannel membrane. Furthermore, it is anticipated that a\nmore effective encryption system will be built by utilizing the bionic\nion channel system’s ease of use and straightforward functionalization.