Controlled clot formation in microfluidic co-flowing devices

Abstract

A stroke is a medical condition in which brain is poorly supplied by blood flow, causing cell death. There are two types, ischemic when the blood vessel is blocked by the formation of a clot, and haemorrhagic, due to bleeding. Ischemic stroke is the most common type of stroke, accounting for 87% of stroke cases. The most common treatment consists of the administration of recombinant tissue plasminogen activator (r-tPA) into the bloodstream. However, such treatment approach presents serious side effects such as internal bleeding or swelling. In that regard, ANGIE project is developing an electromagnetic unit that will allow a controlled drug delivery to a desired clot location by using magnetically active robots. The work hereby presented is mainly focused on the design of a microfluidic device to obtain a control blood coagulation, leading to the generation of clots with well-defined rheology and morphology. In a near future, the anticoagulant drugs activity will be tested on the biomimetic clots-in-chip developed in this TFG project, obtaining preliminary results of the magnetic robot’s effectiveness in the clot’s dissolution process. Toward that goal, the effect of viscosity and flow was evaluated inside a continuous flow microfluidic device. According to the conducted studies, it was observed that by tunning the flow conditions, the mixing point was changed when using the same channel design. Besides, when working with solutions of similar viscosity to whole blood, a wider distribution profile is observed due to the shear rate effect. Once the system was optimized, clot formation was induced by using CaCl2 solutions with whole blood. Furthermore, from blood coagulation studies, it was determined that there was no correlation between the flow conditions and the morphology of the clots formed by using a simple blood recalcification approach