Abstract: To study the dynamic process of DNA, a proper model of particle-laden flow system is presented. Brownian dynamics method is used to simulate the trajectory of DNA in the microchannel where DNA is modeled by the wormlike bead-rod chain. Navier-Stokes equation is numerically solved by using finite element method to obtain the distribution of flow field in three-dimensional rectangular microchannel. The dynamics of DNA under pressure-driven flow can be obtained by considering interactions of flow filed and DNA chain according to the Stokes law. The results show that the DNA chain not only experiences certain deformation but also moves towards the central region of microchannel owing to the coupling effect of hydrodynamic force, random force and bending force. Simulated dynamic characteristics of DNA agree well with the experimental data. When the concentration of DNA is low, the effect of DNA chain on the flow field is very small. The combination of Brownian dynamics and finite element method can be applied to study the polymer behaviors and get a better insight into designing the microchip and biochip.

Key words: Brownian dynamics, DNA, Finite element method, Particle-laden flow system