DNA-coated functional oil droplets

Alessio Caciagli, Mykolas Zupkauskas, Aviad Levin, Tuomas P. J. Knowles, Clément Mugemana, Nico Bruns, Thomas O'Neill, William J. Frith, Erika Eiser

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Abstract

Many industrial soft materials include oil-in-water (O/W) emulsions at the core of their formulations. By using tuneable interface stabilizing agents, such emulsions can self-assemble into complex structures. DNA has been used for decades as a thermoresponsive, highly specific binding agent between hard and, recently, soft colloids. Up until now, emulsion droplets functionalized with DNA had relatively low coating densities and were expensive to scale up. Here, a general O/W DNA-coating method using functional nonionic amphiphilic block copolymers, both diblock and triblock, is presented. The hydrophilic poly(ethylene glycol) ends of the surfactants are functionalized with azides, allowing for efficient, dense, and controlled coupling of dibenzocyclooctane-functionalized DNA to the polymers through a strain-promoted alkyne-azide click reaction. The protocol is readily scalable due to the triblock's commercial availability. Different production methods (ultrasonication, microfluidics, and membrane emulsification) are used with different oils (hexadecane and silicone oil) to produce functional droplets in various size ranges (submicron, ∼20 and >50 μm), showcasing the generality of the protocol. Thermoreversible submicron emulsion gels, hierarchical "raspberry" droplets, and controlled droplet release from a flat DNA-coated surface are demonstrated. The emulsion stability and polydispersity is evaluated using dynamic light scattering and optical microscopy. The generality and simplicity of the method opens up new applications in soft matter, biotechnological research, and industrial advances.

Original languageEnglish
Pages (from-to)10073-10080
Number of pages8
JournalLangmuir
Volume34
Issue number34
Early online date8 Aug 2018
DOIs
Publication statusPublished - 28 Aug 2018

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Keywords

  • oil-in-water
  • emulsions
  • DNA

Cite this

Caciagli, A., Zupkauskas, M., Levin, A., Knowles, T. P. J., Mugemana, C., Bruns, N., ... Eiser, E. (2018). DNA-coated functional oil droplets. Langmuir, 34(34), 10073-10080. https://doi.org/10.1021/acs.langmuir.8b01828