Lattice Boltzmann method and its application in soft matter

Transport phenomena of biological flow and soft matter is very important in studying human disease. This seminar presents modeling work of drug delivery in blood suspensions and circulating tumor cell detection. Methodologically, the Lattice Boltzmann method was employed as the Navier-Stokes fluid solver. The cells were implemented using a coarse grained molecular dynamics model. Besides the fluid and cells, nanoparticles (drug carriers) were also introduced into the model. The coupling method between fluid and solid was based on the Immersed Boundary Method which removes the burden of expensive mesh updating in the traditional Arbitrary Lagrangian Eulerian approach. Effects of shear rate and hematocrit level on nanoparticle (NP) dispersion rate was studied. An empirical formula was proposed and verified to predict the NP dispersion rate under different flow conditions. Influence of membrane deformability, applied pressure, and micropore size on cell translocation time was also studied. Modeling results show that the translocation time is very sensitive to pressure and micropore size but not very sensitive to cells that can pass through the micropore. However, stiffer cells can be blocked by the micropore. Based on cell deformability, the numerical model could be used to optimize the microfluidic design(micropore size, pressure) so that it can efficiently separate cancer cells from other blood cells.