A Concept Towards Pressure-Controlled Microfluidic Networks

Droplet-based microfluidic networks interconnect multiple microfluidic modules which allow to process (e.g., mix, sort, heat, incubate) so-called payload droplets (i.e., droplets containing a biological sample) on a single microfluidic chip. Inside such networks the path of a droplet and, thus, the module which processes it, can be controlled by microfluidic switches. Thus far, these switches are realized by injecting additional control droplets into the network which allow to trigger the switching mechanism by solely exploiting passive hydrodynamic effects. While this eliminates the need of expensive components such as valves, this droplet-controlled switching concept is very sensitive and already slight deviations, e.g., in the control droplet injection could lead to incorrectly triggered switches. In this work, we address this issue by proposing a new concept of pressure-controlled networks which omit the control droplets (and their drawbacks) and, instead, use a single pump in order to drive the switches. Using design automation expertise together with established models, we derive a corresponding blueprint which realizes this idea for a specific network architecture. Simulations based on established methods and design tools confirmed the suitability of the proposed pressure-controlled networks.