“…One key function of lipid A is to anchor lipopolysaccharides (LPS), also known as endotoxins, to the exterior surface of the outermost bilayer in Gram-negative bacteria. Although structural variations exist across species, lipid A typically bears at least six aliphatic tails and one or more phosphate-containing headgroups. , Studies of bacterial lipid A isolated from different species indicate that its homologues form various LLC phases, which depend on both their chemical structures and the surrounding aqueous environment. − ,− The number and length of the lipid tails, in conjunction with the number and protonation state of the anionic phosphate headgroups, dictate the formation of I II , inverse hexagonal (H II ), and L α LLCs as functions of pH, temperature, and aqueous ionic strength. ,,,,, The ability of lipid A to switch between morphologies with different transport properties in response to external stimuli could be a useful property for functional materials (e.g., from the connected water channels of a H II phase to isolated water pools of I II as a molecular “valve”). However, its inherent toxicity, hydrolytic instability, species-to-species variability, and low yields of isolated lipid necessitate the design of new synthetic analogues.…”