Hydrodynamics of Nanoparticle Transport in Fibrin Networks (2012)

Undergraduate: Elizabeth Littauer

Faculty Advisor: Michael Falvo
Department: History

---

Fibrin is critical to the process of blood coagulation and serves in a number of scaffolding capacities in the body. Fibrin monomers associate to form highly extensible protofibrils which interact with each other to form mesh networks. These networks provide structure for blood clots and are subject to shear stress due to blood circulation. Polymer nanoparticle beads can be used as models for biological or synthetic elements, such as platelets or anti-coagulant drugs. Past research has demonstrated that nanoparticle diffusion can reveal the bulk permeability of fibrin networks formed under static non-flow conditions. We have developed a system that flows human platelet-poor plasma through microfluidics channels, which mimic the structure of small arteries and veins. The addition of flow as a variable provides a more physiologically relevant model of fibrin networks maintained within the human circulation system. Flow through these microchannels is laminar and creates heterogeneous fibrin networks of varying densities and permeabilities. Widefield fluorescence imaging shows that fluorescently-labeled fibrin networks formed under flow are oriented parallel to the shear stress of flow. Nanoparticles are shown to be excluded from specific regions of oriented networks. Data analysis of nanoparticle transport through oriented network microenvironments reveals that networks reduce the effect of flow on beads and that bead velocities are consistent with a no-slip boundary condition.