Improved Oxygenation and Hemocompatibility for Microfluidic Artificial Lung via Membrane Microstreaming

Abstract

Microfluidic artificial lung devices seek to capitalize on the increased surface area to volume ratio of the micro scale to increase gas exchange efficiency, allowing for oxygenation of blood with smaller volumes and a smoother flow path. However, such small scales also lead to challenges including coagulation and channel blockage and difficulty in scaling up. This article presents the integration of active mixing to the blood side channel via acoustic microstreaming by an oscillating membrane to enhance gas exchange across that membrane. Tests with fresh ovine blood show reduced biofouling by platelet deposition on the actuated membranes (up to 80% lower surface coverage), which may extend device lifetimes. Coagulation and channel blockage experiments demonstrate reduced coagulation of and channel blockage in taller and actuated channels. O2 gas exchange into ovine blood is improved up to 2.6x compared to the non-actuated control, allowing blood pumped through the device to reach a 95% target for oxygen saturation with channel geometry and flow parameters which would be otherwise unsuitable. Such a design allows for taller channel heights than are typically seen in microfluidic artificial lung devices while maintaining gas exchange efficiency, enabling the device to capitalize on the reduced coagulation associated with the taller, actuated channels, enabling easier fabrication by conventional machining, and allowing for larger throughput per channel branch.