title: Prebiotic Vesicle Formation and the Necessity of Salts.
abstract: Self-assembly is considered one of the driving forces behind abiogenesis and would have been affected by the environmental conditions of early Earth. The formation of membranes is a key step in this process, and unlike large dialkyl membranes of modern cells the first membranes were likely formed from small single-chain amphiphiles, which are environment-sensitive. Fatty acids and their derivatives have been previously characterized in this role without concern for the concentrations of ionic solutes in the suspension. We determined the critical vesicle concentration (CVC) for three single-chain amphiphiles with increasing concentrations of NaCl. All amphiphile species had decreasing CVCs correlated to increasing NaCl concentrations. Decanoic acid and oleic acid were impacted more strongly than monoacylglycerol, likely because of electric shielding of the negatively charged headgroups in the presence of salt. There was no impact on the salt species as 100 mM NaBr, NaCl, and KCl all exhibited the same effect on CVC. This research shows the importance of salt in both the formation of life and in experimental design for aggregation experiments.
authors.affiliation: Department of Chemistry and Biochemistry, Central Connecticut State University, 1615 Stanley St., New Britain, CT, 06050, USA. smaurer@ccsu.edu.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Maurer
authors.affiliation: Department of Chemistry and Biochemistry, Central Connecticut State University, 1615 Stanley St., New Britain, CT, 06050, USA.
authors.forename: Gunarso
authors.initials: G
authors.lastname: Nguyen
mesh_terms: D001965:Bromides / Q000737:chemistry; D003652:Decanoic Acids / Q000737:chemistry*; D019418:Evolution, Chemical; D008081:Liposomes / Q000737:chemistry*; D008823:Micelles; D008956:Models, Chemical; D050178:Monoglycerides / Q000737:chemistry*; D019301:Oleic Acid / Q000737:chemistry*; D000069497:Origin of Life; D011189:Potassium Chloride / Q000737:chemistry; D012965:Sodium Chloride / Q000737:chemistry*; D017670:Sodium Compounds / Q000737:chemistry; D055672:Static Electricity; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: D001965:Bromides; D003652:Decanoic Acids; D008081:Liposomes; D008823:Micelles; D050178:Monoglycerides; D017670:Sodium Compounds; D013501:Surface-Active Agents; D019301:Oleic Acid; D012965:Sodium Chloride; C031071:decanoic acid; D011189:Potassium Chloride; C027938:sodium bromide
keywords: Critical vesicle concentration; Liposome; Protocell; Self-assembly; Surfactant