Tunable spatial heterogeneity in structure and composition within aqueous microfluidic droplets

In this paper, we demonstrate biphasic microfluidic droplets with broadly tunable internal structures, from simple near-equilibrium drop-in-drop morphologies to complex yet uniform non-equilibrium steady-state structures. The droplets contain an aqueous mixture of poly(ethylene glycol) (PEG) and dex...

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Bibliographic Details
Main Authors: Hui, Sophia Lee Su, Wang, Pengzhi, Kun Yap, Swee, Khan, Saif A., Hatton, Trevor Alan
Other Authors: Massachusetts Institute of Technology. Department of Chemical Engineering
Format: Article
Language:en_US
Published: American Institute of Physics 2013
Online Access:http://hdl.handle.net/1721.1/79363
https://orcid.org/0000-0002-4558-245X
Description
Summary:In this paper, we demonstrate biphasic microfluidic droplets with broadly tunable internal structures, from simple near-equilibrium drop-in-drop morphologies to complex yet uniform non-equilibrium steady-state structures. The droplets contain an aqueous mixture of poly(ethylene glycol) (PEG) and dextran and are dispensed into an immiscible oil in a microfluidic T-junction device. Above a certain well-defined threshold droplet speed, the inner dextran-rich phase is “stirred” within the outer PEG-rich phase. The stirred polymer mixture is observed to exhibit a near continuum of speed and composition-dependent phase morphologies. There is increasing interest in the use of such aqueous two-phase systems in microfluidic devices for biomolecular applications in a variety of contexts. Our work presents a method to go beyond equilibrium phase morphologies in generating microfluidic “multiple” emulsions and at the same time raises the possibility of biochemical experimentation in benign yet complex biomimetic milieus.