Can polarity-inverted membranes self-assemble on Titan?

Area of Science:

• Astrobiology
• Chemical Biology
• Planetary Science

Background:

• Understanding life's limits is crucial for identifying biosignatures on exoplanets and within our solar system.
• Lipid bilayer membranes are fundamental to life as we know it.
• Azotosomes, polarity-inverted membranes, were previously suggested as potential life-supporting structures on cryogenic worlds like Titan.

Purpose of the Study:

• To evaluate the thermodynamic viability of azotosome formation.
• To determine if azotosomes can self-assemble under conditions relevant to extraterrestrial environments.

Main Methods:

• Quantum mechanical calculations were employed to assess the thermodynamic stability of azotosomes.
• Thermodynamic viability was compared to the self-assembly of lipid bilayers in water.

Main Results:

• Quantum mechanical calculations indicate that azotosomes are not thermodynamically viable for self-assembly.
• Azotosomes are unlikely to form spontaneously in a manner analogous to lipid bilayers.

Conclusions:

• Cell membranes, as we know them, may not be a universal requirement for life.
• Hypothetical life under stringent anhydrous and low-temperature conditions, such as those on Titan, might not necessitate cell membranes.