Droplet Dispensing from Open to Close Digital Microfluidics

H. Rezaei Nejad, E. Samiei, M. Hoorfar
University of British Columbia, CA

Keywords: dispensing, open, digital microfluidics, droplet, transport

Summary:

There are two types of DMF platforms: open and closed systems. Each platform has its own advantages. For instance, it is easier to access the droplet in the open systems; whereas, the closed system limits the droplet evaporation and facilitates droplet handling in terms of transport and splitting.Despite the flexibility of the closed DMF systems, it is practically difficult to place the sample on the reservoir of such systems. In the current devices, either the DMF platform is dissembled or a micro-capillary needle is implemented for sample injection. The latter case limits the gap between the top and bottom channel and the former case reduces the reproducibility of the device. In this paper, we have introduced a novel design in which the open and close systems are combined together in a way to benefit the accessibility of the open DMF system and have the functionality of the closed DMF systems. The main idea is to have the sample reservoirs on the open section of the platform, and then dispense the desired volumes of the droplet into the closed section of the platform. The feasibility of the proposed design is evaluated for different geometrical factors and applied actuation voltages.