Formation and snake-eating like solubilization mechanisms of rhamnolipid vesicles for oil components and amino acids

Abstract

Rhamnolipid vesicles hold significant potential across a wide range of applications, yet their formation mechanisms and selective solubilization of organic molecules remain elusive. Employing dissipative particle dynamics (DPD) simulations, this study delves deeply into these aspects, uncovering a stepwise formation pathway from dispersed monomers to complex multi-layer vesicle structures. The fusion and growth of three-layer structures were identified as crucial steps in the development of stacked vesicles. Notably, double-chain rhamnolipids (Rh-C10-C10) exhibited enhanced stability in self-assembled structures compared to their single-chain counterparts (Rh-C10). Through a detailed analysis of parameters such as relative concentration distribution, radial distribution function, and density fields, the solubilization process of rhamnolipid vesicles was found to resemble a “snake-eating” mechanism. We also analyzed the solubilization sites, amounts, and vesicle sizes, elucidating the selective solubilization mechanisms of rhamnolipids for representative polar and non-polar compounds in crude oil, anisole and 1-hexene. The selectivity of rhamnolipid vesicles in solubilizing organic molecules was primarily influenced by polar attraction and steric hindrance, which together determined their solubilization sites within the vesicles. Additionally, the solubilization behavior and properties of five types of amino acids within rhamnolipid vesicles were explored, demonstrating analogous solubilization patterns that correlated with amino acid polarity. These results provide a foundation for optimizing the application of rhamnolipid vesicles, paving the way for potential advancements in drug delivery, environmental remediation, and oil recovery processes.