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The electrophoretical stretching of DNA in a hybrid microchannel is analyzed in this paper. The channel comprises a large insulating cylinder and a hyperbolic contraction that can cause the DNA deformation. Brownian dynamics simulation is used to characterize the dynamical stretching process of a long T4 DNA in hybrid microchannels. The computational results show us the larger average extension of DNA in cylinder-hybridized microchannels than that in the single microcontractions due to the prestretched effect of cylinder on DNA. Moreover, the location and the radius of the insulating cylinder in hybrid microchannels have great effects on the stretching behavior of DNA.

Brownian dynamics simulations are used to characterize the electrophoretical stretching process of long T4 DNA in microchannels. When DNA is forced to move through the microchannels, the pure elongational flow generated by electric field gradients in hyperbolic contraction will unravel the molecules of DNA. The effects of hydrodynamic interactions, the strain rate, the Brownian fluctuation, and the initial states of molecules on the stretching dynamics are analyzed in this paper. The computational results show us the weak dependence of polymer dynamics on hydrodynamic interactions in microcontractions. In the case of low Deborah number, the stretching process of a molecule depends on the Brownian fluctuation. However, in the case of high Deborah number, the individualistic stretching behavior can be traced to variations in the starting conformation.