3D Parametric Simulations of Mass Transport and Mechanical Properties of a Microfluidic Barrier-on-Chip Device

Abstract

Organ-on-Chip (OoC) devices enable controlled replication of physiological microenvironments and are increasingly used in biomedical engineering and drug discovery. This study presents a comprehensive 3D simulation-based characterization of mass transport and mechanical properties of a silicon-based Barrier-on-Chip (BoC) device comprising two stacked microfluidic channels separated by a porous Si3N4 membrane. Steady-state laminar flow simulations are performed to obtain the velocity field, after which transient convection-diffusion simulations are conducted to evaluate species transport toward and across the membrane. The mechanical performance of the membrane is analyzed using coupled Fluid-Structure Interaction (FSI) simulations with effective material properties accounting for porosity. Three flow configurations namely coflow, counter-flow, and single-channel flow are investigated across four volumetric flow rates. The results show that both flow configuration and flow rate strongly influence concentration distributions along the membrane. Counter-flow produces the strongest axial concentration gradient, which becomes more spatially uniform at higher flow rates as convection-dominated transport increasingly governs the system. Higher flow rates also result in larger membrane deflections, with counter-flow producing deflections approximately two orders of magnitude greater than co-flow at low flow rates for both configurations. Wall shear stress increases linearly with flow rate, spanning the physiologically relevant ranges for intestinal epithelial and blood-brain barrier endothelial cells. These findings provide quantitative design guidelines for selecting flow configurations and rates based on target concentration gradients, shear stress levels, and mechanical constraints in BoC applications.