Dynamics of Single Polymers in a Stagnation Flow Induced by Electrokinetics

An electrokinetics-induced stagnation flow was created inside a microscale cross-channel. Compared to hydrodynamic-induced microfluidics, this flow system can be readily assembled and the operation is very simple due to a low pressure drop. Through image analysis, a fairly homogeneous, two-dimensional elongational flow was observed. The initial conformation of DNA molecules and residence time inside the flow field play important roles in determining the extent of DNA stretching. A coarse-grain molecular simulation agrees reasonably well with experimental observations.