Design and analysis of a microfluidic bus network with bypass channels

Microfluidics is a multidisciplinary field of research that deals with elementary hydraulic circuits with channels of micrometer size. At this scale, fluids exhibit very specific patterns that cannot be observed at the macro-scale. In particular, vortex forces become negligible, so that the behavior of fluids in the circuit becomes easily controllable and predictable. This technology is currently used in medicine and chemistry to perform specific tasks, such as blood analysis, DNA sequencing, and others. The interest on this technology has been increasing over the last few years and, recently, microfluidic circuits capable of performing simple logical operations have been proposed and experimentally tested, paving the way to a new research branch known as microfluidic networking. In this paper we analyze the design of a microfluidic network with a bus topology, where multiple microfluidic machines are connected to a main channel by means of passive switching elements, realized as T-junctions with bypass (shunt). We mathematically model the system and find the rules to be followed for proper design and dimensioning of such a microfluidic network. We then propose a preliminary performance analysis that gives some insights into the complex interrelations among the different elements of the microfluidic network.