Jeudi 29 février à 11h, salles des séminaires IRPHE
Abstract: Natural porous systems, such as soil, membranes, and biological tissues exhibit heterogenous structures that result in a wide range of length-scales and velocity-scales. The transport of soft matter, such as colloidal particles, droplets, cancer cells, and microorganisms within these structures is key for a broad range of environmental and medical applications including soil remediation, drug delivery and filtration. During the first segment of this seminar, my emphasis will be on an important micro-structural characteristic shared among these systems: dead-end pores interconnected within a network of percolating channels. I will present how we quantify the transport of colloidal particles, and dynamics of motile bacteria in a structurally heterogeneous porous medium engineered in microfluidic channels. Utilizing a combination of experiments, numerical simulations, and statistical modelling, I will show how the macroscopic transport of such particles is linked to the microstructural features. Additionally, I will elucidate how such transport is regulated for bacteria through cell motility, chemotaxis, and biological sensing (i.e., quorum sensing), underscoring the impact of dead-end pores.
In the second segment of this seminar, I will highlight on my ongoing investigations related to migration of circulating tumor cells (CTCs) in the microenvironment of the vascular network. I will present a microfluidic pore-network model designed to investigate the effects of heterogeneous constrictions on CTC migration, trapping, and death. The model introduces heterogeneity in constriction size based on a vascular capillary network, inducing a complex velocity field within the circulating fluid. Additionally, the inclusion of CTCs as a secondary phase, circulating and trapped within the heterogeneous porous system, alters the fluid velocity field, leading to a two-way coupling effect that further influences the medium's heterogeneity, porosity, and permeability. In this part of the talk, we will present some preliminary results showcasing the coupling effect between CTCs and the fluid flow, shedding light on the development of a statistical model to predict CTC breakthrough through the network.