On the Improvement of Alveolar-Like Microfluidic Devices for Efficient Blood Oxygenation

In this work, alveolar-like microfluidic devices are studied with a horizontal membrane arrangement that demonstrate a great potential as small-scale blood oxygenator. The design criteria for the fabricated devices are to maximize the oxygen saturation level and minimize liquid chamber volume while ensuring the physiological blood flow in order to avoid thrombus formation and channel blockage during operation. The liquid chamber architecture is iteratively modified upon analysis of the fluid dynamics by computer modeling. Accordingly, two alveolar type architectures are fabricated, Alveolar Design 1 (AD1) and Alveolar Design 2 (AD2), and evaluated for oxygenation of sheep blood. The attained O ₂ transfer rate at 1 mL min ⁻¹ of blood flow rate for both devices is rather similar: 123 and 127 mL min ⁻¹ m ⁻² for AD1 and AD2 microfluidic devices, respectively. Among the studied, AD2 type geometry would lead to the lowest pressure drop and shear stress value upon implementation in a scaled microfluidic artificial lung (μAL) to satisfy oxygenation requirements of a 2.0 kg neonate.