Formation of droplet networks that function in aqueous environments

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Abstract

Aqueous droplets in oil that are coated with lipid monolayers and joined through interface bilayers1,2 are useful for biophysical measurements on membrane proteins2,3,4,5. Functional networks of droplets that can act as light sensors, batteries and electrical components can also be made by incorporating pumps, channels and pores into the bilayers2,6. These networks of droplets mimic simple tissues7, but so far have not been used in physiological environments because they have been constrained to a bulk oil phase. Here, we form structures called multisomes in which networks of aqueous droplets with defined compositions are encapsulated within small drops of oil in water. The encapsulated droplets adhere to one another and to the surface of the oil drop to form interface bilayers that allow them to communicate with each other and with the surrounding aqueous environment through membrane pores. The contents in the droplets can be released by changing the pH or temperature of the surrounding solution. The multicompartment framework of multisomes mimics a tissue7,8,9 and has potential applications in synthetic biology and medicine.

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Figure 1: Schematics and photographs of multisomes.
Figure 2: Free energy landscape.
Figure 3: Measurement of ionic currents through αHL pores.
Figure 4: Communication by diffusion through αHL pores.
Figure 5: pH- and temperature-dependent release of encapsulated contents into the aqueous environment.

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Acknowledgements

The authors thank E. Mikhailova for the αHL protein prepared by in vitro transcription/translation, and Q. Li for the αHL from S. aureus. The authors also thank M. Wallace for the loan of a microscope objective. This work was supported by grants from the National Institutes of Health and the European Commission's Seventh Framework Programme Revolutionary Approaches and Devices for Nucleic Acid Analysis Consortium. G.V. was supported by an Engineering and Physical Sciences Research Council Life Sciences Interface Doctoral Training Centre studentship.

Author information

G.V., A.J.H. and H.B. planned the research. G.V. performed the experiments, data analysis and modelling. G.V. and H.B. wrote the paper.

Correspondence to Hagan Bayley.

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