Omni-Liquid Droplet Manipulation Platform

Droplet manipulation is of importance in a wide range of applications in biomedicine, chemical analysis, and synthesis, among other fields. Over the past decade, extensive efforts are made to develop different strategies of transporting droplets by using various external stimuli. However, these methods could fail to manipulate some complex liquids with a low surface tension, high viscosity, or corrosivity. Herein, a magnetic digital microfluidics platform (MDMP) that is capable of manipulating almost all liquid droplets is described. The MDMP is designed by combining a magnet-controlled deformable substrate and a slippery liquid-infused surface. Such a structure allows creating a site-specific gravitational potential gradient to propel droplets under different conditions. It is demonstrated that this MDMP can rapidly and reversibly transport various liquids for specimen sorting, chemical reactions, and accelerating mixing. It is envisioned that this universal droplet manipulation device will lay the foundation to achieve a wide variety of autonomous open channel fluidic device applications.