Aminosilane/Oleic Acid Vesicles as Model Membranes of Protocells

Abstract

Oleic acid vesicles represent good models of membrane protocells that could have existed in prebiotic times. Here, we report the formation, growth polymorphism, and dynamics of oleic acid spherical vesicles (1-10 μm), stable elongated vesicles (>50 μm length; 1-3 μm diameter), and chains of vesicles (pearl necklaces, >50 μm length; 1-3 μm diameter) in the presence of aminopropyl triethoxysilane and guanidine hydrochloride. These vesicles exhibit a remarkable behavior with temperature: spherical vesicles only are observed when keeping the sample at 4 °C for 2 h, and self-aggregated spherical vesicles occur upon freezing/unfreezing (-20/20 °C) samples. Rather homogeneous elongated vesicles are reformed upon heating samples at 80 °C. The phenomenon is reversible through cycles of freezing/heating or cooling/heating of the same sample. Deuterium NMR evidences a chain packing rigidity similar to that of phospholipid bilayers in cellular biomembranes. We expect these bilayered vesicles to be surrounded by a layer of aminosilane oligomers, offering a variant model for membrane protocells.

Self-Assembly and Rheological Properties of a Pseudogemini Surfactant Formed in a Salt-Free Catanionic Surfactant Mixture in Water

“…Polarized microscopy observations of the L α phases in the single L α phase region and the L 1 /L α two-phase region reveal the presence of the stripe textures (inset of Figure 2B, Figure S3), which demonstrates the existence of the lamellar phase. 6 When c C 14 -S-C 14 exceeds 110 mmol·L −1 , precipitates are observed in the L α phase. pH and conductivity measurements indicated that the C 14 -S-C 14 aqueous solution is slightly acidic with a pH value of around 5 and the conductivity is low, typically below 20 μS·cm −1 in the single L α phase.…”

Insight into carbon quantum dot–vesicles interactions: role of functional groups

“…The basic ingredients for their formation (synthetically) are mainly fatty acids, lipids, phospholipids, surfactant, polymers, and others. 1–3 A popular member of this family is the liposome, which can be synthesized from lipids and phospholipids, and is gradually becoming one of the most studied systems in biomedical research. As a natural process, bacteria can also produce vesicles as a metabolic product known as outer membrane vesicles (OMVs), which are actually responsible for their cellular communication.…”

Fatty Acid Vesicles and Coacervates as Model Prebiotic Protocells

“…Other reports demonstrated that fatty acids with different alkyl chain lengths could also selfassemble into vesicles. [29][30][31][32][33][34][35] The large variety of fatty acids found in ancient rocks [36] further comforted the possible role of fatty acid vesicles as prebiotic protocells: the "lipid world", or rather, the "fatty acid world", was born. [37] Since then, extensive studies pioneered by the Luisi, Szostak and Deamer groups have explored the plausible role of fatty acid vesicles as prebiotic protocells capable of nutrient uptake, growth and division, [38][39][40] and able to host RNA catalysis [41] and self-replication.…”

“…[29][30][31][32][33][34][35] The large variety of fatty acids found in ancient rocks [36] further comforted the possible role of fatty acid vesicles as prebiotic protocells: the "lipid world", or rather, the "fatty acid world", was born. [37] Since then, extensive studies pioneered by the Luisi, Szostak and Deamer groups have explored the plausible role of fatty acid vesicles as prebiotic protocells capable of nutrient uptake, growth and division, [38][39][40] and able to host RNA catalysis [41] and self-replication. [42,43] However, fatty acid vesicles are only stable on a fairly narrow pH range, [32,44] and readily disassemble or precipitate in the presence of divalent cations [35,41] or at physiological salt concentrations; [45] yet metal ions are often crucial for biopolymer catalysis and folding, and would have likely been present in prebiotic ponds.…”