Stretching and migration of DNA by solvent elasticity in an oscillatory flow

Abstract

A model with solution viscoelasticity is proposed to explain the ratchetlike stretching of DNA by a symmetric ac electric field in polymer solutions. In this model, DNA is stretched by the interaction between the fluid elasticity and the oscillatory flow induced by DNA. Predictions of the model are confirmed by DNA stretching experiments performed in various polymer solutions and the corresponding rheological measurements of the solutions. In particular, experiments have verified that a net migration of stretched DNA in polymer solutions can be induced by a zero-mean asymmetric ac electric field. This last finding cannot be explained by other existing models.

Coupling electrokinetics and rheology: Electrophoresis in non-Newtonian fluids

“…However, in microfluidic devices and capillary electrophoresis, for example, electric fields are routinely used to drive electrokinetic transport in fluids whose rheology does not follow Newton's ideal: e.g. polymer solutions [9][10][11][12][13] or biofluids [14][15][16]. Indeed, there has been significant recent interest in electro-osmotic flows of such complex, or non-Newtonian, fluids [17][18][19][20][21][22][23][24][25][26][27][28][29][30].…”