Design and assessment of a pure hydrodynamic microfluidic switch

The feasibility of using microfluidic technologies for communication and networking among Labs-On-a-Chip (LoCs), in order to increase reusability, their effectiveness and flexibility, has been already demonstrated in recent works. LoCs are devices, in the size of few centimeters, characterized by μ-scale channels in which small volumes of fluids, either in the form of a continuous stream or of sequences of discrete droplets, move in order to deliver chemical or biological samples to a given destination entity in the microfluidic circuit. They are usually realized through monolithic devices. Samples are processed by passing them through a preset sequence of fixed microfluidic channels. We propose and assess a pure-hydrodynamic switching element in which the path followed by a sample can be controlled through a series of junctions simply modulating the distance between droplets flowing in the microfluidic channel.