A model of random fiber networks that describes the sieving of particles during gel electrophoresis.

A model is presented to describe the sieving of particles during gel electrophoresis by considering the movement of a spherical particle through a random network of straight, rigid fibers. The movement of the particle through the network is approximated by a discrete model of the network composed of parallel planes containing fibers through which the particle must pass. Unlike previous models this model does not assume that the rate of movement is proportional to the proportion of cross-sectional area available to the particle. The results provide a new justification for approximately linear Ferguson plots and suggest that for large particles, Ferguson plots may become nonlinear.