Issue 24, 2023

Alignment-free construction of double emulsion droplet generation devices incorporating surface wettability contrast

Abstract

Although polydimethylsiloxane (PDMS) is a versatile and easy-to-use material for microfluidics, its inherent hydrophobicity often necessitates specific hydrophilic treatment to fabricate microchip architectures for generating double emulsions. These additional processing steps frequently lead to increased complexity, potentially creating barriers to the wider use of promising microfluidic techniques. Here we describe an alignment-free spatial hydrophilic PDMS patterning technique to produce devices for the creation of double emulsions using combinations of PDMS and PDMS/surfactant bilayers. The technique enables us to achieve selective patterning and alignment-free bonding, producing reliable and reproducible water-in-oil-in-water W/O/W droplet emulsions. Our method involves processing devices in a vertical orientation, with the wetting transition contrast being achieved simply by imaging whilst adjusting the PDMS pouring speed (using a mobile phone, for example). We successfully obtain hydrophilic surfaces without distinguishable hydrophobic recovery using a range of surfactant concentrations. Droplet emulsions were produced with low coefficients of variation aligned with those generated with other, more complex, techniques (e.g. 3.8% and 3.1% for the inner and outer diameters, respectively). As a further example, the methods were also demonstrated for liposome production. In future we anticipate that the technique may be applied to other fields, including e.g. reagent delivery, DNA amplification, and encapsulated cell studies.

Graphical abstract: Alignment-free construction of double emulsion droplet generation devices incorporating surface wettability contrast

Supplementary files

Article information

Article type
Paper
Submitted
05 Jul 2023
Accepted
06 Oct 2023
First published
06 Oct 2023
This article is Open Access
Creative Commons BY license

Lab Chip, 2023,23, 5173-5179

Alignment-free construction of double emulsion droplet generation devices incorporating surface wettability contrast

Y. Aslan, O. McGleish, J. Reboud and J. M. Cooper, Lab Chip, 2023, 23, 5173 DOI: 10.1039/D3LC00584D

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