10 research outputs found
Free Energy Barrier for Electric Field Driven Polymer Entry into Nanoscale Channels
Free energy barrier for entry of a charged polymer into a nanoscale channel
by a driving electric field is studied theoretically and using molecular
dynamics simulations. Dependence of the barrier height on the polymer length,
the driving field strength, and the channel entrance geometry is investigated.
Squeezing effect of the electric field on the polymer before its entry to the
channel is taken into account. It is shown that lateral confinement of the
polymer prior to its entry changes the polymer length dependence of the barrier
height noticeably. Our theory and simulation results are in good agreement and
reasonably describe related experimental data
Electric-field-driven polymer entry into asymmetric nanoscale channels
The electric-field-driven entry process of flexible charged polymers such as
single stranded DNA (ssDNA) into asymmetric nanoscale channels such as
alpha-hemolysin protein channel is studied theoretically and using molecular
dynamics simulations. Dependence of the height of the free-energy barrier on
the polymer length, the strength of the applied electric field and the channel
entrance geometry is investigated. It is shown that the squeezing effect of the
driving field on the polymer and the lateral confinement of the polymer before
its entry to the channel crucially affect the barrier height and its dependence
on the system parameters. The attempt frequency of the polymer for passing the
channel is also discussed. Our theoretical and simulation results support each
other and describe related data sets of polymer translocation experiments
through the alpha-hemolysin protein channel reasonably well