Alignment-free construction of double emulsion droplet generation devices incorporating surface wettability contrast.
Yunus AslanOlivia McGleishJulien ReboudJonathan M CooperPublished in: Lab on a chip (2023)
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.
Keyphrases
- single cell
- high throughput
- liquid chromatography
- magnetic resonance
- high resolution
- nucleic acid
- stem cells
- magnetic resonance imaging
- circulating tumor
- fatty acid
- bone marrow
- single molecule
- contrast enhanced
- molecular dynamics simulations
- circulating tumor cells
- computed tomography
- escherichia coli
- biofilm formation
- mesenchymal stem cells
- photodynamic therapy
- smoking cessation