Enhanced polymer capture speed and extended translocation time in pressure-solvation traps

TL;DR

This paper demonstrates how pressure-solvation traps, enhanced by polyvalent cations, can significantly speed up polymer capture and extend translocation times in nanopore sequencing, with validated scaling laws and electrostatic insights.

Contribution

It introduces a pressure-solvation trap mechanism that improves polymer capture and translocation control in nanopores, supported by experimental data and theoretical scaling laws.

Findings

Polyvalent cations trigger like-charge attraction, speeding capture.

Pressure-solvation traps extend polymer translocation time.

Electrostatic barriers influence liquid flow during capture.

Abstract

The efficiency of nanopore-based biosequencing techniques requires fast anionic polymer capture by like-charged pores followed by a prolonged translocation process. We show that this condition can be achieved by setting a pressure-solvation trap. Polyvalent cation addition to the KCl solution triggers the like-charge polymer-pore attraction. The attraction speeds-up the pressure-driven polymer capture but also traps the molecule at the pore exit, reducing the polymer capture time and extending the polymer escape time by several orders of magnitude. By direct comparison with translocation experiments [D. P. Hoogerheide et al., ACS Nano 8, 7384 (2014)], we characterize as well the electrohydrodynamics of polymers transport in pressure-voltage traps. We derive scaling laws that can accurately reproduce the pressure dependence of the experimentally measured polymer translocation velocity and time. We also find that during polymer capture, the electrostatic barrier on the translocating molecule slows down the liquid flow. This prediction identifies the streaming current measurement as a potential way to probe electrostatic polymer-pore interactions.