Mechanically activated ionic transport across single-digit carbon nanotubes

Abstract

Fluid and ionic transport at nanoscale recently highlighted a wealth of exotic behaviours [1-14]. However, the artificial nanofluidic devices [15-18] are still far from the advanced functionalities existing in biological systems, such as electrically and mechanically activated transport [19, 20]. Here we focus on the ionic transport through 2 nm-radius individual multiwalled carbon nanotubes (CNT), under the combination of mechanical and electrical forcings. Our findings evidence mechanically activated ionic transport under the form of an ionic conductance which depends quadratically on the applied pressure. Our theoretical study relates this behaviour with the complex interplay between electrical and mechanical drivings, and shows that the superlubricity of CNT [4-8, 21] is a prerequisite to attain mechanically activated transport. The pressure sensitivity shares similarities with the response of biological mechanosensitive ion channels [19, 20] observed here for the first time in an artificial system. This paves the way to build new active nanofluidic functionalities inspired by the complex biological machinery.

From Water Solutions to Ionic Liquids with Solid State Nanopores as a Perspective to Study Transport and Translocation Phenomena

“…The high ILs viscosities would imply less of an influence of electroosmotic flow and allow for necessarily excluding complex nonlinear ion transport functionalities arising due to a competition of advective and diffusive ion transport. [52,199] As IL ions have lower diffusion constants and higher viscosity than water solutions, the Péclet number is still reasonable such that interesting nanofluidic phenomena may take place in a temperature-dependent fashion.…”

Towards artificial mechanosensing

“…Alternative to mature technologies based on silicon or III-V semiconductors, the ability to combine two-dimensional (2D) layers of transition metal dichalcogenides (TMDCs) in van der Waals heterostructures 1 has recently opened inexpensive pathways to obtain on-demand optoelectronic properties by confining electrons and excitonselectron-hole pairs bound by Coulomb interactions -in arrays of zero-dimensional (0D) potential wells formed by atomic moiré patterns, which are periodic variations of the alignment between atoms in adjacent layers. Despite several promising results [2][3][4][5] , the influence of strain and other sample imperfections on the geometry of the moiré potential landscape and optical behaviour of TMDC heterostructures has not yet been directly investigated. Now, writing in Nature Materials, Yusong Bai and collaborators 6 report correlated real-space imaging of strain-induced one-dimensional (1D) moiré patterns and optical measurements of the corresponding excitonic emission in MoSe 2 / WSe 2 heterobilayers, showing that strain engineering can be used as an effective route to create anisotropic potentials for electrons on the nanoscale and tune the optical response of van der Waals heterostructures.…”

“…1b), the superlattice turns the flatland into a dotland for electrons and excitons, leading to a wide range of phenomena that have been predicted [7][8][9] and observed [2][3][4][5] . However, very different exciton properties have been reported in the same type of TMDC heterobilayers [2][3][4][5] , suggesting a more complex underlying structure than an ideal moiré lattice. Decoding the origin of the observed contradicting phenomena…”

“…Achieving replicas of these sensory systems is one of the goals of nanotechnology as it would allow us to not only mimic such sensory functionalities in artificial systems such as minimal cells 4 , but also to better understand their roles in living organisms. Now, writing in Nature Materials, Alice Marcotte et al 5 demonstrate an artificial nanofluidics system composed of a single-digit-diameter carbon nanotube that mimics the ion transport response of biological mechanosensitive ion channels.…”

“…c, experimentally measured streaming currents (I str ) through CNT as a function of pressure drop for distinct membrane potential differences (-25 mV to 25 mV). Panel c adapted with permission from ref 5 ,. Springer Nature Ltd.…”