In situformation, manipulation, and imaging of droplet-encapsulated fibrin networks

In this study, we investigate the formation, manipulation, and imaging of droplet-encapsulated fibrin networks using tailored microfluidic devices. The objective is to understand how different droplet microenvironments affect the aggregation and deformation of fibrin, a protein crucial for blood clotting. Methodologically, we encapsulate protein components in separate droplets that are merged via electrocoalescence and either allowed to flow continuously or to park for evolution of isotropic networks. High-resolution fluorescence microscopy is employed to visualize the networks formed in microchannels. Our results reveal that aggregation is significantly influenced by the flow fields encountered by the droplets. Under stopped-flow conditions, a stable droplet-spanning network emerges after a ripening period, and the network exhibits elastic properties under low deformation rates. Conversely, when deformation rates exceed a specific threshold, shape transitions occur, leading to increased protein densification due to hydrodynamic forces. These findings underscore the dynamic interplay between flow conditions and fibrin network characteristics, highlighting the potential of microfluidic tools in advancing biomolecular studies.