Oxygen Transport in Nanoporous SiN Membrane Compared to PDMS and Polypropylene for Microfluidic ECMO

Abstract

Extracorporeal Membrane Oxygenation (ECMO) serves as a crucial intervention for patients with severe pulmonary dysfunction by facilitating oxygenation and carbon dioxide removal. While traditional ECMO systems are effective, their large priming volumes and significant blood-contacting surface areas can lead to complications, particularly in neonates and pediatric patients. Microfluidic ECMO systems offer a promising alternative by miniaturizing the ECMO technology, reducing blood volume requirements, and minimizing device surface area to improve safety and efficiency. This study investigates the oxygen transport performance of three membrane types-- polydimethylsiloxane (PDMS), polypropylene, and a novel nanoporous silicon nitride (SiN) membrane--in a microfluidic ECMO platform. While nanoporous membranes rely on pore-mediated diffusion and PDMS on polymer lattice diffusion, results show no significant differences in device oxygenation efficiency (p > 0.05). Blood-side factors, including the diffusion rate of oxygen through the red blood cell (RBC) membrane, RBC residence time, and hemoglobin binding kinetics, were identified as primary bottlenecks. Even computational models of a hypothetical infinitely permeable membrane corroborate the limited impact of membrane material. These findings suggest a shift in ECMO design priorities from membrane material to blood-side enhancements. This research provides a foundation for optimizing ECMO systems.