Direct observation of <italic>λ</italic>-DNA molecule reversal movement within microfluidic channels under electric field with single molecule imaging technique

Direct observation of λ-DNA molecule reversal movement within microfluidic channels under electric field with single molecule imaging technique

Yang Fengyun¹, Wang Kaige^{1, †,}, Sun Dan¹, Zhao Wei^{1, 2}, Wang Hai-qing¹, He Xin¹, Wang Gui-ren², Bai Jin-tao¹

Velocity direction of DNA molecule moving within the microchannel. (a) The schematic diagram of competition between electrophoresis and electroosmosis forces in the microchannel. The DNA molecule is negatively charged, the black arrow stands for the direction of electrophoresis velocity, while the red arrow is the velocity direction of electroosmotic flow. The movement direction of the negative ion under the electric field was defined as the positive direction of velocity (black dotted arrow). (b) When v_EOF > v_EP, the v_real of DNA molecules is negative. When v_EOF < v_EP, the v_real is a positive value.