How channel elasticity enhances and directs flow in dendritic microfluidic networks

Pressure drop per unit length is key to limiting the magnitude of flow in vascular systems and fluidic devices. This study presents a straightforward, pressure-responsive method to enhance flow compliance in dendritic microfluidic systems by manipulating the local elasticity. A series of dendritic fluidic networks with varying numbers of elastic elements were developed using replica molding of the elastomer polydimethylsiloxane in a single fabrication step. These elements, consisting of thin elastic membranes, deform under pressure, unlike rigid walls. The geometry and hydrodynamic properties of the networks were characterized by flow velocity measurements and fluorescence microscopy. The most elastic network showed a significant increase in compliance with thin membranes replacing rigid walls, resulting in a non-linear increase in flow rate. Selective placement of elastic elements allowed pressure-controlled flow directionality. This approach reduces pressure loss, does not require complicated fabrication steps, and allows dynamic flow manipulation in specific regions of microfluidic networks.