title: Double Emulsion Generation Using a Polydimethylsiloxane (PDMS) Co-axial Flow Focus Device.
abstract: Double emulsions are useful in a number of biological and industrial applications in which it is important to have an aqueous carrier fluid. This paper presents a polydimethylsiloxane (PDMS) microfluidic device capable of generating water/oil/water double emulsions using a coaxial flow focusing geometry that can be fabricated entirely using soft lithography. Similar to emulsion devices using glass capillaries, double emulsions can be formed in channels with uniform wettability and with dimensions much smaller than the channel sizes. Three dimensional flow focusing geometry is achieved by casting a pair of PDMS slabs using two layer soft lithography, then mating the slabs together in a clamshell configuration. Complementary locking features molded into the PDMS slabs enable the accurate registration of features on each of the slab surfaces. Device testing demonstrates formation of double emulsions from 14 µm to 50 µm in diameter while using large channels that are robust against fouling and clogging.
authors.affiliation: Department of Pharmaceutical Chemistry, University of California, San Francisco.
authors.forename: Russell H
authors.initials: RH
authors.lastname: Cole
authors.affiliation: Joint UCSF/UCB Bioengineering Graduate Group, University of California, San Francisco.
authors.forename: Tuan M
authors.initials: TM
authors.lastname: Tran
authors.affiliation: Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco; California Institute for Quantitative Biosciences, University of California, San Francisco; adam.abate@ucsf.edu.
authors.forename: Adam R
authors.initials: AR
authors.lastname: Abate
mesh_terms: D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D004655:Emulsions / Q000737:chemistry; D004867:Equipment Design; D005898:Glass / Q000737:chemistry; D056656:Lab-On-A-Chip Devices; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods; D014867:Water / Q000737:chemistry; D017155:Wettability
chemical_list: D004129:Dimethylpolysiloxanes; D004655:Emulsions; D014867:Water; C013830:baysilon