  The efficiency of nanopore-based polymer sensing devices depends on the fast
capture of anionic polyelectrolytes by negatively charged pores. This requires
the cancellation of the electrostatic barrier associated with repulsive
polymer-pore interactions. We develop a correlation-corrected theory to show
that the barrier experienced by the polymer can be efficiently overcome by the
addition of multivalent cations into the electrolyte solution. Cation
adsorption into the pore enhances the screening ability of the pore medium with
respect to the bulk reservoir which translates into an attractive force on the
polymer. Beyond a critical multivalent cation concentration, this
correlation-induced attraction overcomes the electrostatic barrier and triggers
the adsorption of the polymer by the like-charged pore. It is shown that
like-charge polymer-pore attraction is suppressed by monovalent salt but
enhanced by the membrane charge strength and the pore confinement. Our
predictions may provide enhanced control over polymer motion in translocation
experiments.
