Optical and Magnetic Approaches to Microfluidic Blood Diagnostics

Thesis (Ph.D.)--University of Washington, 2020Critical bleeding manifests in cardiovascular disease and trauma. As a patient bleeds, there is a loss of red blood cells, responsible for the delivery of oxygen throughout the body, and this loss is known as anemia. In trauma patients, a stable clot must form to stop bleeding. Conversely, stiff clots can form occlusions in blood vessels, which leads to stroke or myocardial infarction. Thus, evaluating platelet function could improve our understanding of a bleeding risk. The goal of this dissertation is to develop an approach that can potentially assess anemia and bleeding risks for a patient. To address this, I have split this dissertation into four aims. Aim 1: A microfluidic approach was taken to detect anemia in whole blood. Specifically, with this approach, severe and moderate anemia levels can be detected accurately. The use of a microfluidic device allows this approach to be rapid, use low volume of blood, and easily integrated with other blood diagnostic microfluidic approaches. Aim 2: An optical benchtop platform was developed to measure the platelet forces in a microfluidic assay. The benchtop platform detected significant differences in platelet forces for patients that undergo blood transfusion within 24 hours of hospital admittance and those who did not undergo blood transfusion and healthy controls. Aim 3: Magnetic microscale actuators were integrated into the platelet force assay. A refined technique to embed iron particles into microstructures was explored and a new way to actuate the magnetic posts was designed and modeled. Aim 4: Using the assay developed in Aim 3, the mechanobiology of platelet-rich plugs during formation was investigated. The results from the assay indicated that plugs stiffen in response to the contractile force of platelets and the applied force from magnetic actuators