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Abstract
Prior to the emergence of cellular life, there must have been an abiotic analogue to the cell -- also known as the protocell. To flourish, they should have performed key functions enabling growth, and ensuring their survival and propagation. While researchers study a variety of model protocell systems, the study of model protocells assembled from fatty acid vesicles is lacking in comparison to the abundant literature on phospholipid vesicles. There is evidence that the existence of fatty acids predated life on Earth. Moreover, the highly dynamic nature of fatty acid vesicles is not well documented in the origins of life context. There is a need to explore the behaviour of fatty acid vesicles in systems which mimic real world environments.
I explored the flocculation behaviour of vesicles in environments of mechanical stress, monovalent salt and particles including minerals. I also explored the effect of RNA-relevant divalent cations on fatty acid vesicles, as well as changes due to pH fluctuation. The findings of this project suggest that fatty acid vesicles are able to flocculate under quite low concentrations of monovalent salt, and that such flocs can incorporate particles including mineral particles which are relevant for catalysing RNA-related reactions. Furthermore, I found that after vesicles have been formed, they are surprisingly robust in conditions that inhibit vesicle formation. These results provide evidence that protocells assembled from simple building blocks such as fatty acids are quite robust and may persist in challenging environments, and that their flocculation behaviour may have co-localised other processes pertaining to the origins of life.
