Finite element analysis of oxygen transport in microfluidic cell culture devices with varying channel architectures, perfusion rates, and materials

Numerical simulations were done both as an exploration into the nature of oxygen transport within microfluidic cell culture devices and an investigation of the relative importance of various design parameters. A rectangular channel comprised of an oxygen permeable polymer layer bonded to a glass substrate seeded with a monolayer of oxygen-consuming cells was modeled. Oxygen transport by both convection and diffusion within the cell culture media and by diffusion in the polymer layer were explored using finite element analysis. Stiff spring analysis was applied at the interface between these two regions to ensure a continuous flux of O₂ across the boundary. The O₂ utilization of the cells was approximated by a constant flux of oxygen from the bottom of the channel. The model was verified against an analytical solution from the literature. Design parameters including flow rate, diffusive layer thickness, and material selection were manipulated within the model to determine their relative importance in ensuring adequate supplies of oxygen for cell growth. The solubility and diffusivity of oxygen within the polymer layer were found to be key parameters in determining the amount of oxygen available to the cells, along with the flow rate of the media perfusing the system. These explorations will enable rational design choices to be undertaken during the implementation of microfluidic devices for cell culture.