Development of a microfluidic device for blood oxygenation by photocatalysis

Abstract

Recent statistics provided by the American Lung Association assert that over 400,000 Americans die every year from lung disorders and more than 35 million are now living with symptoms of lung disease. Mortality rates of heart disease and certain cancers have declined in recent years partly due to improvements in diagnostic testing and the development of targeted medical technologies. Such improvements have not translated over to the treatment of lung disease and lung cancer. The goal of the artificial respiration project is to create a self-contained, mobile oxygen supply that is suitable for implantation and that can potentially replace acute or chronically disabled lungs. A novel microfluidic device for the oxygenation of whole blood has been developed. The device couples a semiconductor, titanium dioxide (TiO₂), thin film that generates oxygen through photocatalysis with a microfluidic network that facilitates diffusion of the dissolved oxygen to red blood cells. While true pulmonary respiration relies on passive diffusion of oxygen gas from the environment to the blood, the proposed device differs in that it generates oxygen directly from the water in blood plasma. This thesis focuses on the work done to fabricate and characterize the semiconductor photocatalyst, design the integrated microfluidic chip, and validate its capacity to oxygenate blood in real-time. Blood oxygenation experiments show that the microfluidic device exhibiting the best performance produced 4.06 mL of oxygen per 100 mL of blood, nearly two-thirds of the oxygen transferred in the lung.

(cont.) The flux of oxygen at the photocatalyst surface was 1.11 x 10-3 mmol O₂/ (cm² - min). The O₂ flux is nearly two orders of magnitude larger than that of any other fluidic device for blood oxygenation to date. The results from the proof-of-concept microfluidic device are promising and are a step towards the realization of a photocatalytic artificial lung.