Hydrophobic gating occurs when the ionic current flowing through a nanopore is hindered by the reversible formation of a vapour bubble inside the pore. The bubble formation (pore drying) and collapse (pore wetting) changes the pore conductance. An applied external voltage substantially alters hydrophobic gating, typically stabilising the wet state (electrowetting).
The interplay between current modulation by hydrophobic gating and modulation of the gate by an external voltage may result in fascinating yet largely unexplored features such as current/voltage hysteresis and, more generally, history dependent conductance.
ElectroHG proposes to study the dependence of wetting and drying rates on the external voltage for both model solid state nanopores with heterogeneous surface chemistry along the pore axis, and in biological nanopores obtained mutating several rings in the β-barrel of pore-forming proteins such as Anthrax and Aerolysin.
These systems will clarify the effect of geometry and surface chemistry on electrowetting of nanopores, to be used as constructive parameters for bioengineered nanopores.
These ambitious goals will be achieved by deploying Molecular Dynamics (MD) simulations equipped with rare-event methods which can only run on European-level HPC resources. The insights gained in ElectroHG will improve the understanding of hydrophobic gating dynamics and of its possible role in biological pores, possibly providing guidelines for the design of a new class of devices for neuromorphic computing.
Sapienza University of Rome, Italy.