Pulsed-field acceleration: the electrophoretic behavior of large spherical particles in agarose gels

In agarose gel electrophoresis, periodically inverting or interrupting the applied field may greatly accelerate the migration of polystyrene microspheres, in a manner varying with pulse times, and the observed zones are made sharper. The particles concerned are just large enough that under constant field they appear not to enter the gel at all or to migrate very slowly: and merely lowering the applied field may also enhance their electrophoretic migration, though to a lesser extent than with field pulsing. These effects may be accounted for by gel mesh flexibility which, varying with the nature of the migrating species, may either help or hinder migration.