Development of an integrated microfluidic platform for oxygen sensing and delivery

Abstract

Treatment for end stage lung disease has failed to benefit from advances in medical technology that have produced new treatments for cardiovascular disease, certain cancers, and other major illnesses in recent years. As a result, end stage lung disease remains a devastating condition with few therapeutic options. To address the need for improved methods of respiratory life support, a novel technology was developed capable of generating oxygen directly from water present in blood plasma. This technology is intended to provide a self-contained, mobile oxygen supply suitable for implantation or extracorporeal oxygenation in support of an acute or chronically disabled lung. The core technology couples an optoelectronic metal oxide film with a microfluidic capillary network to facilitate oxygen exchange with flowing blood and replicate pulmonary capillary respiration. This thesis focuses on the optimization of this microfluidic capillary network with respect to hemocompatibility, mass transfer, and dissolved oxygen detection. Microfluidic capillary devices were fabricated from silicone rubber using multilayer soft lithography to create dense 2D networks of bifurcating channels. To quantify the effectiveness of mass transfer in various channel geometries under differing experimental conditions, a mathematical model of oxygen convection and diffusion was generated. A novel integrated optical oxygen sensor based on an oxygen-quenched luminescent dye was developed to detect oxygen concentrations within the microfluidic device. Mass transfer within the microfluidic oxygenator was characterized experimentally, employing the integrated optical sensor, and analytically, using the convective model.

(cont.) Excellent agreement was found between experimental and analytical results. We conclude that the microfluidic platform achieves rapid and efficient diffusion of oxygen into a liquid medium, effectively mimicking the function of the pulmonary system. The combination of precise oxygen delivery and detection, integrated into a miniature device, is widely applicable both to the photolytic artificial lung and to a broader class of applications related to detection of chemical species in biological microdevices.