Ratcheted diffusion transport through crowded nanochannels.


Type
Article
Change log
Authors
Lappala, Anna 
Zaccone, Alessio 
Terentjev, Eugene M 
Abstract

The problem of transport through nanochannels is one of the major questions in cell biology, with a wide range of applications. In this paper we discuss the process of spontaneous translocation of molecules (Brownian particles) by ratcheted diffusion: a problem relevant for protein translocation along bacterial flagella or injectosome complex, or DNA translocation by bacteriophages. We use molecular dynamics simulations and statistical theory to identify two regimes of transport: at low rate of particle injection into the channel the process is controlled by the individual diffusion towards the open end (the first passage problem), while at a higher rate of injection the crowded regime sets in. In this regime the particle density in the channel reaches a constant saturation level and the resistance force increases substantially, due to the osmotic pressure build-up. To achieve a steady-state transport, the apparatus that injects new particles into a crowded channel has to operate with an increasing power consumption, proportional to the length of the channel and the required rate of transport. The analysis of resistance force, and accordingly--the power required to inject the particles into a crowded channel to overcome its clogging, is also relevant for many microfluidics applications.

Description
Keywords
cond-mat.soft, cond-mat.soft
Journal Title
Sci Rep
Conference Name
Journal ISSN
2045-2322
2045-2322
Volume Title
3
Publisher
Springer Science and Business Media LLC
Sponsorship
Engineering and Physical Sciences Research Council (EP/F032773/1)