The use of glycolipids inserted in color-changeable polydiacetylene vesicles, as targets for biological recognition

Topochemical organizations of conjugated diacetylenic acid photochemically polymerize to afford UV-visible absorbing polymers. Under the effect of an external stress caused by combination of the biomolecules to be recognized with the glycolipids on the vesicle surface, changes of conformation in the polymer backbone may result in a color change. Thus, monolayers and vesicles made of conjugated diacetylenic acid and a certain amount of glycolipids can be polymerized as far as the topochemical organization is not disrupted. In the presence of a protein (lectin, IgG, virus, etc.) or a microorganism (E. coli) able to bind with the glycolipid, the recognition at the interface resulted in a color change from blue to red. The synthesis of new glycolipids, and the study of their embedment into polydiacetylenic supramolecular assemblies allowed optimizing recognition parameters with regard to the structures of conjugated diynoic acids, the ideality of polydiacetylenic/glycolipidic mixtures, the polydiacetylene/glycolipid molar ratios, pH or vesicle sizes. The rapidity and the sensitivity of the phenomenon (often visible to the naked eye) together with the simplicity of its quantification (UV-visible spectrum) render it a good candidate for the development of biosensors.