Volumetric monitoring of aqueous two phase system droplets using time-lapse optical coherence tomography

We present a volumetric monitoring method to observe the morphological changes of aqueous two phase system (ATPS) droplets in a microfluidic system. Our method is based on time-lapse optical coherence tomography (OCT) which allows the study of the dynamics of ATPS droplets while visualizing their 3D structures and providing quantitative information on the droplets. In this study, we monitored the process of rehydration and deformation of an ATPS droplet in a microfluidic system and quantified the changes of its volume and velocity under both static and dynamic fluid conditions. Our results indicate that time-lapse OCT is a very promising tool to evaluate the unprecedented features of droplet-based microfluidics.