Influence of polysaccharides on the dynamic self-assembly of medium-chain fatty acid vesicles and hydrolysis of decanoic acid anhydrides

Hydrolysis of fatty acid anhydrides involves fatty acid vesicle formation and autocatalytic hydrolysis. Previous studies focused on the effect of biopolymers on vesicle formation or on autocatalytic reactions, however, the influence of polysaccharides on a system where the self-assembly of fatty acid vesicles and the hydrolysis of fatty acid anhydrides coexist remains unknown. In this paper, three polysaccharides, sodium chondroitin sulfate (CSA), sodium alginate (SA) and 2-hydroxyethyl cellulose (2-HEC) were selected to investigate the effect of crowded media on the decanoic acid vesicle formation and the autocatalytic hydrolysis of decanoic anhydride. The results showed that the rate of hydrolysis of decanoic anhydride increased in CSA or SA but decreased in 2-HEC. Further investigation revealed that the size of vesicles in CSA decreased in the early stage of vesicle formation but increased in 2-HEC. In the CSA-vesicle system, elastic behavior dominates, while 2-HEC- and SA-vesicles show more viscous behavior. In addition, the significantly increased membrane fluidity in CSA or in SA supports self-assembly of decanoic acid vesicles and autocatalytic hydrolysis, which is the opposite in the case of 2-HEC. This research provides new insights into the self-assembly of fatty acid vesicles and vesicle-catalyzed reactions with polysaccharides in crowded conditions.