Reversible transformation of an acid/soap vesicle by glucose oxidation

Abstract A vesicle consisting of oleic acid and oleate exhibits a reversible transformation in the presence of glucose. A vesicle with double-spherical structure transforms into a starfish-like shape, and then returns to the double-spherical structure. This reversible transformation occurs two times in this experiment. The transformation is caused by glucose oxidase that is contained in the vesicle membrane. The enzyme oxidizes the glucose surrounding the vesicle to form gluconic acid in the presence of water. The vesicle itself is capable of generating a local pH change required for the reversible transformation. To the best of our knowledge, this is the first example of an abiotic molecular assembly that generates rhythmic motion by glucose oxidation and the resultant pH change.