Electrophoretic Mobility of Double-Stranded DNA in Polymer Solutions and Gels with Tuned Structures

We report a systematic experimental study on the migration behavior of double-stranded DNA (dsDNA) in polymer networks with precisely controlled network structures. The electrophoretic mobility (mu) appeared to be a power law function of the number of base pairs (n), mu similar to n(-gamma) with 0.36 < gamma < 1.46. The variance in gamma has been commonly explained using the reptation model with constraint release or using the entropic trapping (ET) model. However, our results indicated that the mu values were expressed as products of a power law function and an exponential function of n, which differs from any of the existing models. The power law function terms corresponded to the existing models, the Rouse model or the reptation model. In polymer gels, we observed a crossover from the Rouse to the reptation model with an increase in n, while the migration behavior in polymer solutions always obeyed the Rouse model. These results revealed that the continuous change in gamma was accommodated by the exponential function terms.