Mixed fatty acid-phospholipid protocell networks.

Area of Science:

• Origin of life studies
• Biophysics
• Astrobiology

Background:

• Self-assembled membranes of fatty acids and phospholipids offer permeability and stability, crucial for early cell development.
• Solid surfaces can enhance the formation of model protocells, aiding in the study of primitive cell origins.

Purpose of the Study:

• To investigate the solid surface-assisted formation of primitive mixed-surfactant membrane compartments (model protocells).
• To analyze the structural and functional properties of these compartments, particularly their permeability and growth dynamics.

Main Methods:

• Formation of model protocells from multilamellar lipid reservoirs with varying fatty acid and phospholipid ratios.
• Observation of spontaneous self-transformation into interconnected compartments via nanotube networks on solid substrates.
• Measurement of permeability coefficients for fluorescein and RNA through the generated compartments.

Main Results:

• Achieved spontaneous formation of interconnected, closed surfactant containers from mixed amphiphiles on solid surfaces.
• Observed colony-like growth in some fatty acid-containing compartments.
• Demonstrated increased permeability coefficients for fluorescein (up to 7 × 10^-6 cm s^-1) and RNA (up to 3.5 × 10^-6 cm s^-1) in compartments derived from fatty acid-containing membranes.

Conclusions:

• Surface-assisted formation of protocells from mixed amphiphiles is a viable mechanism for early cell emergence.
• Mixed surfactant membranes exhibit enhanced permeability, supporting the development of primitive cellular functions.
• The observed self-organization and growth dynamics provide insights into plausible pathways for the origin of life.