Tube-in-tube oxygen saturator enabling precise and dynamic control of liquid-phase oxygen concentrations for human cell culture applications

This study demonstrates the feasibility of using a Teflon-AF-based tube-in-tube saturator for fast and precise adjustment of oxygen concentrations in liquids, extending its relevance to human cell culture applications beyond organ-on-chip systems. The system achieves high, near-saturation oxygen concentrations of the liquid phase, with performance influenced by various parameters such as temperature, volume flow rate, and tube length. We demonstrate that the tube-in-tube saturator exhibits high sensitivity to variations in these parameters at low oxygen concentrations, whereas this sensitivity diminishes as saturation is approached. To elucidate the underlying mass transfer processes, kinetic experiments were combined with computational fluid dynamics simulations. The simulation results are in good agreement with the experimental data, and the developed model enables a reliable prediction of oxygen concentrations in the liquid phase under varying operating conditions. Owing to its design, performance, versatility, and portability, this system introduces a new approach for the precise and rapid control of oxygen concentrations in liquids for microscale and macroscale human cell culture applications, offering seamless integration with natural vascular or artificial perfusion networks.