Growth and division of active droplets provides a model for protocells

Abstract

It has been proposed that during the early steps in the origin of life, small droplets could have formed via the segregation of molecules from complex mixtures by phase separation. These droplets could have provided chemical reaction centres. However, whether these droplets could divide and propagate is unclear. Here we examine the behaviour of droplets in systems that are maintained away from thermodynamic equilibrium by an external supply of energy. In these systems, droplets grow by the addition of droplet material generated by chemical reactions. Surprisingly, we find that chemically driven droplet growth can lead to shape instabilities that trigger the division of droplets into two smaller daughters. Therefore, chemically active droplets can exhibit cycles of growth and division that resemble the proliferation of living cells. Dividing active droplets could serve as a model for prebiotic protocells, where chemical reactions in the droplet play the role of a prebiotic metabolism.

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Figure 1: Division of chemically active droplets.
Figure 2: Reaction rates and energy supply.
Figure 3: Reaction flux, concentration profile and diffusion flux in an effective droplet model.
Figure 4: Stationary droplet radii and stability diagrams.
Figure 5: Cycles of growth and divisions.

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Acknowledgements

We would like to thank D. Tang for a critical reading of our manuscript.

Author information

All authors developed the project and wrote the paper together. Numerical solutions of the continuum model were obtained by R.S. and D.Z.

Correspondence to Frank Jülicher.

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The authors declare no competing financial interests.

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Zwicker, D., Seyboldt, R., Weber, C. et al. Growth and division of active droplets provides a model for protocells. Nature Phys 13, 408–413 (2017). https://doi.org/10.1038/nphys3984

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