MACROMOLECULAR SEPARATION THROUGH A POROUS SURFACE

A new technique for the separation of macromolecules is proposed and i nvestigated. A thin mesh with pores comparable to the radius of gyrati on of a free chain is used to filter chains according to their length. Without a field it has previously been shown that the permeability de cays 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 re solution of separation. We also propose a modified screen containing a n array of holes with barblike protrusions running parallel to the sur face. When static friction is present between the macromolecule and th e protrusion, some of the chains get trapped for long durations of tim e. By using this and a periodic modulation of an applied electric fiel d, high resolution can be attained. (C) 1997 American Institute of Phy sics.