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Résumé |
In Nature exceptional permeability and selectivity properties are reached,
for example ion channels are able to distinguish with high throughput very
similar ions like Sodium and Potassium. The paradigm change as compared to
nanoscale technology is that these biological filters are
out-of-equilibrium, submitted to either thermal or active fluctuations –
for example of the pore constriction. Here we investigate how
out-of-equilibrium fluctuations of a pore may affect the translocation
dynamics, in particular dispersion coefficients. Our findings demonstrate
a complex interplay between transport and surface wiggling and elucidate
the impact of pore agitation in a broad range of artificial and biological
porins, but also, at larger scales, in vascular motion in fungi,
intestinal contractions and microfluidic surface waves. These results open
up the possibility that transport across membranes can be actively tuned
by external stimuli, with potential applications to nanoscale pumping,
osmosis and dynamical ultrafiltration. |
