Microfluidic fabrication of water-in-water (w/w) jets and emulsions

• Published in: Biomicrofluidics Vol. 6; no. 1; pp. 012808 - 012808-9
• Main Authors: Varnell, Jason, Weitz, David A.
• Format: Journal Article
• Language: English
• Published: United States American Institute of Physics 01.03.2012
• Subjects: Special Topic: Selected Papers from the Second Conference on Advances in Microfluidics and Nanofluidics and Asia-Pacific International Symposium on Lab on Chip, Singapore, 2011 (Guest Editors: Zhiping Wang and Charles Yan Chun)
• ISSN: 1932-1058; 1932-1058
• DOI: 10.1063/1.3670365

We demonstrate the generation of water-in-water (w/w) jets and emulsions by combining droplet microfluidics and aqueous two-phase systems (ATPS). The application of ATPS in microfluidics has been hampered by the low interfacial tension between typical aqueous phases. The low tension makes it difficult to form w/w droplets with conventional droplet microfluidic approaches. We show that by mechanically perturbing a stable w/w jet, w/w emulsions can be prepared in a controlled and reproducible fashion. We also characterize the encapsulation ability of w/w emulsions and demonstrate that their encapsulation efficiency can be significantly enhanced by inducing formation of precipitates and gels at the w/w interfaces. Our work suggests a biologically and environmentally friendly platform for droplet microfluidics and establishes the potential of w/w droplet microfluidics for encapsulation-related applications.