A theory for the electrophoretic separation of DNA in polymer solutions

We present a mathematical model of DNA capillary electrophoresis in polymer solutions based on nonentangling collisions between DNA and polymer molecules. Using videomicroscopy images of DNA migrating through polymer solutions, we propose a modified transient entanglement coupling mechanism for DNA separations that includes nonentangling DNA/polymer collisions. We show that a mathematical model based on individual nonentangling DNA/polymer collisions is able to predict the mobilities of DNA in solutions of low molecular mass polymer. We compare the model predictions to mobility data for separations of DNA in a range of concentrations for solutions of both hydroxypropylcellulose (Mw 100,000) and hydroxyethylcellulose (Mw 139,000). The model relies on one fitted parameter, the time constant for the interaction between the DNA and polymer molecules, which is based on the physical properties of DNA and polymers.