Electro-"Wicking" into Dielectric-Coated Microstructures

Currently, microfluidic systems are highly expected to advance Internet of Things (IoT)-based sensing systems targeting liquid samples, for applications in various fields such as epidemiology and the environment. Among them, digital microfluidics, driven by electrowetting on dielectric (EWOD) is a promising candidate for realizing IoT-based microfluidic systems. However, in a typical two dimensional (2D) digital microfluidic device, it is difficult to introduce liquid samples into the device from outside. To overcome this difficulty, in this work, we propose a method to manipulate liquids by integrating two technologies: capillary flow in three-dimensional (3D) microstructures and EWOD. The EWOD driven capillary flow realized in 3D microscructures allows an IoT-based system not only to collect liquid from outside of the device but also to expel it from the device, which even enables the generation of droplet arrays in the structure.