Physics of size selectivity.

  title={Physics of size selectivity.},
  author={Roland Roth and Dirk Gillespie},
  journal={Physical review letters},
  volume={95 24},
We demonstrate that two mechanisms used by biological ion channels to select particles by size are driven by entropy. With uncharged particles in an infinite cylinder, we show that a channel that attracts particles is small-particle selective and that a channel that repels water from the wall is large-particle selective. Comparing against the extensive density-functional theory calculations of our model, we find that the main physics can be understood with surprisingly simple bulk models that… 

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