Development of an autonomous picoliter droplet array generating device with a centrifugal microfluidic system

Abstract

In this study, we propose and develop an autonomous picoliter droplet array-generating device using a centrifugal microfluidic system. Droplet arrays play a crucial role in the advancement of chemical analyses, such as digital quantification and digital PCR. In digital quantification, it is important to standardize the size of the droplets and ensure the ease of analysis of the detection reactions within each droplet. Hence, we developed a device that can form droplets of a predetermined size within pre-arranged cup structures simply by flowing liquid and successfully controlled the flow for generating picoliter droplet arrays. The flow control was conducted simply by rotation, and it was not necessary to customize the centrifuge. By optimizing the cup arrangement and these spaces, the device realized that approximately140 pL of highly uniform droplets with an area concentration as high as 32 pieces per square millimeter. Moreover, by implementing an evaporation-prevention function, it was confirmed that the droplets could be retained for more than 30 min. Owing to its simplicity, it is expected to make a significant contribution to the widespread adoption of digital quantification and advancement of analysis.