Macromolecular separation through a porous surface

TL;DR

This paper introduces a novel macromolecular separation technique using porous surfaces and pulsed fields, achieving higher resolution by controlling permeability decay and trapping chains with surface protrusions and electric field modulation.

Contribution

It presents a new separation method employing porous meshes and pulsed fields, enhancing resolution through exponential decay of permeability and chain trapping mechanisms.

Findings

Permeability decays exponentially with chain length under pulsed fields.

Modified screens with protrusions trap chains for improved separation.

Electric field modulation enhances resolution significantly.

Abstract

A new technique for the separation of macromolecules is proposed and investigated. A thin mesh with pores comparable to the radius of gyration of a free chain is used to filter chains according to their length. Without a field it has previously been shown that the permeability decays as a power law with chain length. However by applying particular configurations of pulsed fields, it is possible to have a permeability that decays as an exponential. This faster decay gives much higher resolution of separation. We also propose a modified screen containing an array of holes with barb-like protrusions running parallel to the surface. When static friction is present between the macromolecule and the protrusion, some of the chains get trapped for long durations of time. By using this and a periodic modulation of an applied electric field, high resolution can be attained.