Electrophoresis simulated with the cage model for reptation

Abstract

The cage model for polymer reptation is extended to simulate gel electrophoresis. With increasing electric field strength E, the drift velocity v of a long polymer with length L shows three different regimes: (a) the linear regime where v~E/ L; (b) the quadratic regime where v~E^2 , independent of the length of the polymer; and (c) a regime where the velocity decreases exponentionally with E. The transition between regimes (a)! and (b) occurs for field strengths E~L^-1 . The transition between regimes (b)! and (c) occurs for some value Eh , for which L^-1 <<Eh <<1. The behavior in the first two regimes is in agreement with earlier reports on simulations of the Duke-Rubinstein model, and with experimental work on DNA polymers in agarose gel. The third regime is not reported for the Duke-Rubinstein model, probably because in this model, stored length cannot compile into hernias.