Microfluidic blood oxygenators with integrated hollow chambers for enhanced air exchange from all four sides

Traditionally, cylindrical hollow fibers have been used as gas exchange interfaces in commercial oxygenators due to their simplicity of fabrication and the ability to oxygenate a large volume of blood by flowing blood around a bundle of cylindrical hollow fibers, which are served for the introduction of the gases. Over the past decade, newer microfluidic designs have been developed to overcome some of the limitations of the hollow fiber technology such as the lack of the ability to provide biomimetic flow paths to reduce shear stress and hence potentially initiation of the blood coagulation cascade as well as the difficulty to reduce the distance between fibers to decrease the resistance to diffusion of gases on the blood compartment while achieving higher efficiency of gas exchange. Nevertheless, the microfluidic designs that have been reported in the literature only provide gas exchange interfaces on one or two sides of their rectangular cross-section blood perfusion channels, thereby limiting gas exchange efficiency. Here, we report on a new design where closed gas chambers are placed adjacent to the blood perfusion channels so that the gas exchange into the blood can occur on all four sides. We demonstrate that such a design will increase the gas exchange surface area without affecting the channel's geometry or its flow characteristics. The gas exchange performance of the new design is enhanced up to 223% Compared with its equivalent double-sided gas exchange design. These new designs are expected, in the future, to help microfluidic oxygenators combine the best characteristics of both the microfluidic and hollow fiber designs to achieve superior performance.