Disentangling density fluctuations and membrane formation in liquid methane

Cell membranes are complex structures that are robust enough to withstand changes in temperature and pressure, yet are stable and flexible enough to cope with a vast library of cellular processes. However, the mild conditions on Earth - conditions where water is liquid and membranes can be thermally stable - are famously scarce in the vastness of space. Recent data collected by the Cassini-Huygens probe, and subsequently studied by computer modelling has shown that some nitrogen-containing “tholin” molecules may be able to spontaneously form membrane-like structures in the cold liquid methane lakes on Titan, one of the moons of Saturn. We recently obtained tantalising evidence of this self-assembly by cooling a solution of the tholin 1-aminopentane in supercritical methane to cryogenic temperatures. Here we propose to build on this pilot work in two ways: by obtaining corresponding background measurements at each statepoint studied previously (for which an individual background is required due to density effects) and to study the “best candidate” tholin acrylonitrile, having favoured the less hazardous 1-aminopentane while refining our experimental protocol.