(3dt) Biofluids and Nanofluids Under Flow: Applications in Biomedical Engineering, Nanotechnology and Energy Harvesting

My research interests focus on the dynamics of biofluids and nanofluids under flow. Two examples of such systems that I have extensively studied are suspensions of rigid non-spherical nanoparticles and blood. In this poster, I will focus on my current work on the flow induced segregation behavior in blood. Blood is a multicomponent mixture comprising mostly of red-blood-cells (RBCs) along with trace amounts of other components like leukocytes, platelets, and circulating tumor cells (in the case of cancer). Under physiological flow conditions both the leukocytes and the platelets segregate near the walls of the blood vessel, a phenomenon commonly known as margination, while the RBCs tend to migrate away from the walls. The key physical differences between RBCs, leukocytes, and platelets are their relative size and rigidity: the leukocytes are larger than RBCs, while the platelets are smaller; both are considerably stiffer than RBCs. However, how these differences in properties lead to the observed segregation behavior is poorly understood. Using detailed boundary integral simulations, we systematically delineate the effect of size and rigidity on the segregation behavior in particle mixtures and relate these to the observations of margination of leukocytes and platelets in blood flow. To gain a mechanistic understanding of these results, we introduce a novel hydrodynamic-Monte Carlo simulation technique, which incorporates two of the main ingredients of flow dynamics in confined suspensions: the wall induced migration and pair collisions. In particular, the model clarifies the important role played by heterogeneous collisions, i.e. collisions between two different species in a mixture, in the observed segregation behavior. The insights and tools presented in this poster will be helpful, e.g., in designing drug delivery particles for optimal vascular targeting and for designing microfluidic devices for separating/enriching trace components of blood. In this poster, I will also present several examples of future research directions, including the role of blood flow in cancer treatment, mechanical energy harvesting using dielectric droplets, programmable assembly of patterned nanoparticles under flow and separation of non-spherical nanoparticle mixtures in microfluidic devices.