Source: https://www.nature.com/articles/s41565-019-0415-0?error=cookies_not_supported&code=da0c7386-c17a-494e-9f52-60b0870bd7b2
Timestamp: 2019-04-20 18:24:45+00:00

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Water is a ubiquitous liquid with unique physicochemical properties, whose nature has shaped our planet and life as we know it. Water in restricted geometries has different properties than in bulk. Confinement can prevent low-temperature crystallization of the molecules into a hexagonal structure and thus create a state of amorphous water. To understand the survival of life at subzero temperatures, it is essential to elucidate this behaviour in the presence of nanoconfining lipidic membranes. Here we introduce a family of synthetic lipids with designed cyclopropyl modifications in the hydrophobic chains that exhibit unique liquid-crystalline behaviour at low temperature, which enables the maintenance of amorphous water down to ~10 K due to nanoconfinement. The combination of experiments and molecular dynamics simulations unveils a complex lipid–water phase diagram in which bicontinuous cubic and lamellar liquid crystalline phases that contain subzero liquid, glassy or ice water emerge as a competition between the two components, each pushing towards its thermodynamically favoured state.
Journal peer review information Nature Nanotechnology thanks Tianshu Li and the other anonymous reviewer(s) for their contribution to the peer review of this work.
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We acknowledge J. S. Siegel for insights and useful discussions, and W. K. Fong for assistance with the SAXS experiments. This work is based on experiments performed at the Swiss spallation neutron source SINQ, Paul Scherrer Institute, Villigen, Switzerland. Support by SNF Sinergia grant CRSII2_154451 to E.M.L. and R.M. is acknowledged. R.M. further acknowledges support from SNF grants 200020_178997 and 200021_172767.
These authors contributed equally: Livia Salvati Manni, Salvatore Assenza.
E.M.L. and R.M. designed and directed the study. L.S.M. developed the lipid synthesis, produced lipidic mesophases, performed SAXS and WAXS experiments, and coordinated the NMR, DSC and FWS experiments. S.A. set up and performed molecular dynamics simulations. M.D. synthesized, purified and performed NMR characterization of the lipids. J.J.V. performed DSC experiments. F.J. collected and interpreted FWS data. S.J. collected and interpreted diffusion NMR data. O.Z. directed the NMR studies. L.S.M., S.A., E.M.L. and R.M. wrote the manuscript with contributions from all the authors.
Correspondence to Ehud M. Landau or Raffaele Mezzenga.

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