Simulation of advanced microfluidic systems with dissipative particle dynamics

Abstract

Computational Fluid Dynamics (CFD) is widely and successfully used in standard design processes for microfluidic mu TAS devices. But for an increasing number of advanced applications involving the dynamics of small groups of beads, blood cells or biopolymers in microcapillaries or sorting devices, novel simulation techniques are called for. Representing moving rigid or flexible extended dispersed objects poses serious difficulties for traditional CFD schemes. Meshless, particle-based simulation approaches, such as Dissipative Particle Dynamics (DPD) are suited for addressing these complicated flow problems with sufficient numerical efficiency. Objects can conveniently be represented as compound objects embedded seamlessly within an explicit model for the solvent. However, the application of DPD and related methods to realistic problems, in particular the design of microfluidics systems, is not well developed in general. With this work, we demonstrate how the method appears when used in practice, in the process of designing and simulating a specific microfluidic device, a microfluidic chamber representing a prototypical bead-based immunoassay developed in our laboratory (Glatzel et al. 2006a, b; Riegger et al. 2006)

Quantifying Compressibility and Slip in Multiparticle Collision (MPC) Flow Through a Local Constriction

“…has been used in Equation (A6) to replace W in terms of W , and Equation (30) has been used in Equation (A7) to replace W in terms of Q. The relationship in Equation (A9) follows from using w poi as given in Equation (22), in flow rate Equation (30).…”

“…The relationship in Equation (A9) follows from using w poi as given in Equation (22), in flow rate Equation (30). Although this relationship is exact for w = w poi in an unconstricted portion of the cylinder, it is also assumed to hold throughout the constriction, thus potentially giving rise to some error in the analysis.…”

“…Additional particle-based methods applied to blood flow studies in microvessels, for which deformable particles are modeled separately from the fluid in which they are suspended, include simulations with MPC [28,29] and DPD [30][31][32][33]. In [32], a Y-shaped bifurcation is considered, and [29] consider a complex flow domain.…”

Computer simulations of charged colloids in alternating electric fields

“…The collision steps are determined from pair interactions between DPD beads, which are coarse-grained and include a dissipative friction term and a random thermal noise. In the origin setup [96,97,98], the colloids are made of the same DPD beads as the fluid. The relative motion of those beads is frozen and the dynamics of the assembly is governed by the movement of the centers of mass and the rotation dynamics of the body axes.…”

The in-silico lab-on-a-chip

“…It has been used extensively to model complex fluids such as colloidal suspensions, emulsions and polymers [26] and has become a key method for the study of the blood microrheology [55,70]. DPD resolves cells at a sub-micron scale to simulate microfluidic [60] and drug delivery systems [44], reaching time scales that have been previously accessible only to Navier-Stokes solvers [18]. State of the art DPD solvers are based on extensions of Molecular Dynamics (MD) software packages such as LAMMPS [54] and HOOMD-Blue [3] targeting both CPU-only and GPUaccelerated supercomputers.…”