Dehydration Enhances Prebiotic Lipid Remodeling and Vesicle Formation in Acidic Environments

pH-Responsive Self-Assembled Compartments as Tuneable Model Protocellular Membrane Systems

Prebiotically plausible single-chain amphiphiles are enticing as model protocellular compartments to study the emergence of cellular life, owing to their self-assembling properties. Here, we investigated the self-assembly behaviour of mono-N-dodecyl phosphate (DDP) and mixed systems of DDP with 1-dodecanol (DDOH) at varying pH conditions. Membranes composed of DDP showed pH-responsive vesicle formation in a wide range of pH with a low critical bilayer concentration (CBC). Further, the addition of DDOH to DDP membrane system enhanced vesicle formation and stability in alkaline pH regimes. We also compared the high-temperature behaviour of DDP and DDP:DDOH membranes with conventional fatty acid membranes. Both, DDP and DDP:DDOH mixed membranes possess packing that is similar to decanoic acid membrane. However, the micropolarity of these systems is similar to phospholipid membranes. Finally, the pH-dependent modulation of different phospholipid membranes doped with DDP was also demonstrated to engineer tuneable membranes with potential translational implications.

A Physicochemical Consideration of Prebiotic Microenvironments for Self-Assembly and Prebiotic Chemistry

The origin of life on Earth required myriads of chemical and physical processes. These include the formation of the planet and its geological structures, the formation of the first primitive chemicals, reaction, and assembly of these primitive chemicals to form more complex or functional products and assemblies, and finally the formation of the first cells (or protocells) on early Earth, which eventually evolved into modern cells. Each of these processes presumably occurred within specific prebiotic reaction environments, which could have been diverse in physical and chemical properties. While there are resources that describe prebiotically plausible environments or nutrient availability, here, we attempt to aggregate the literature for the various physicochemical properties of different prebiotic reaction microenvironments on early Earth. We introduce a handful of properties that can be quantified through physical or chemical techniques. The values for these physicochemical properties, if they are known, are then presented for each reaction environment, giving the reader a sense of the environmental variability of such properties. Such a resource may be useful for prebiotic chemists to understand the range of conditions in each reaction environment, or to select the medium most applicable for their targeted reaction of interest for exploratory studies.

Novel Apparatuses for Incorporating Natural Selection Processes into Origins-of-Life Experiments to Produce Adaptively Evolving Chemical Ecosystems

Origins-of-life chemical experiments usually aim to produce specific chemical end-products such as amino acids, nucleic acids or sugars. The resulting chemical systems do not evolve or adapt because they lack natural selection processes. We have modified Miller origins-of-life apparatuses to incorporate several natural, prebiotic physicochemical selection factors that can be tested individually or in tandem: freezing-thawing cycles; drying-wetting cycles; ultraviolet light-dark cycles; and catalytic surfaces such as clays or minerals. Each process is already known to drive important origins-of-life chemical reactions such as the production of peptides and synthesis of nucleic acid bases and each can also destroy various reactants and products, resulting selection within the chemical system. No previous apparatus has permitted all of these selection processes to work together. Continuous synthesis and selection of products can be carried out over many months because the apparatuses can be re-gassed. Thus, long-term chemical evolution of chemical ecosystems under various combinations of natural selection may be explored for the first time. We argue that it is time to begin experimenting with the long-term effects of such prebiotic natural selection processes because they may have aided biotic life to emerge by taming the combinatorial chemical explosion that results from unbounded chemical syntheses.