Programmable electrowetting with channels and droplets

In this work, we demonstrate continuous and discrete functions in a digital microfluidic platform in a programmed manner. Digital microfluidics is gaining popularity in biological and biomedical applications due to its ability to manipulate discrete droplet volumes (nL-pL), which significantly reduces the need for a costly and precious biological and physiological sample volume and, thus, diagnostic time. Despite the importance of discrete droplet volume handling, the ability of continuous microfluidics to process larger sample volumes at a higher throughput cannot be easily reproduced by merely using droplets. To bridge this gap, in this work, parallel channels are formed and programmed to split into multiple droplets, while droplets are programmed to be split from one channel, transferred and merged into another channel. This programmable handling of channels and droplets combines the continuous and digital paradigms of microfluidics, showing the potential for a wider range of microfluidic functions to enable applications ranging from clinical diagnostics in resource-limited environments, to rapid system prototyping, to high throughput pharmaceutical applications.