  Ion transporters in Nature exhibit a wealth of complex transport properties
such as voltage gating, activation, and mechanosensitive behavior. When
combined, such processes result in advanced ionic machines achieving active ion
transport, high selectivity, or signal processing. On the artificial side,
there has been much recent progress in the design and study of transport in
ionic channels, but mimicking the advanced functionalities of ion transporters
remains as yet out of reach. A prerequisite is the development of ionic
responses sensitive to external stimuli. In the present work, we report a
counterintuitive and highly nonlinear coupling between electric and
pressure-driven transport in a conical nanopore, manifesting as a strong
pressure-dependence of the ion conductance. This result is at odds with
standard linear response theory and is akin to a mechanical transistor
functionality. We fully rationalize this behavior on the basis of the coupled
electrohydrodynamics in the conical pore by extending the
Poisson-Nernst-Planck-Stokes framework. The model is shown to capture the
subtle mechanical balance occurring within an extended spatially charged zone
in the nanopore. The pronounced sensitivity to mechanical forcing offers leads
in tuning ion transport by mechanical stimuli. The results presented here
provide a promising avenue for the design of tailored membrane functionalities.
