A Microfluidic Approach to Model Deep Vein Thrombosis*

Deep vein thrombosis (DVT)  is a dangerous and painful condition in which blood clots form in deep veins. Mechanisms of clot development remain unclear, however specific flow patterns in veins, especially around the valve flaps play a fundamental role (Bovill and van der Vliet, 2011). To study DVT, we fabricated valves made of polyethylene glycol diacrylate in-situ in a microfluidic device achieving control over geometry and elasticity using stop-flow lithography (Dendukuri et al., 2007; Wexler et al., 2013). We independently varied the elasticity of each valve’s leaflet to obtain symmetrical or asymmetrical characteristics. To analyse the velocity profiles we exploit ghost particle velocimetry (Buzzaccaro et al., 2013; Riccomi et al., 2018) and we study particle accumulation, mimicking clot formation, by flowing polystyrene particles. We found that particles tend to accumulate at the tip of symmetric leaflet valves whereas in an asymmetrical valve a predominant accumulation behind the more flexible valve leaflet happens. This is important as a major risk factor for DVT in the elderly is a reduced elasticity of their valves.