Networked Labs-on-Chips (NLoCs): A Passive Droplet Routing Concept for Two-Phase Flow Microfluidics

Droplet based two-phase flow microfluidic systems provide a promising platform for the realization of Labs-on-Chips (LoCs). Here, samples e.g. of DNA, proteins, cells, as well as organisms are injected into droplets. Then, these droplets flow in an immiscible continuous flow inside closed channels and are passed through modules executing operations such as mixing, heating, and detecting -- realizing the desired medical/biochemical experiment. The use of closed channels allows for a long-term incubation and storage of droplets. However, existing approaches still suffer from a rather complex control-layer (i.e. for controlling modules based on dielectrophoresis or valves) and/or lack in flexibility (i.e. are designed for a specific laboratory experiment only). These problems have recently been addressed by extensions to passively route droplets through the system -- allowing for a dynamic/conditioned behavior within one experiment and the support of different complex experiments on the same chip. This eventually results in a concept known as Networked Labs-on-Chips (NLoCs).