Unique Effects of Cyclodextrins on the Formation and Colorimetric Transition of Polydiacetylene Vesicles

Summary: The effects of cyclodextrins (CDs) on the formation and color changes of polymerized 10,12-pentacosadiynoic acid (PCDA) vesicles have been investigated. The strategy used in this study focuses on three different stages in which the CDs can play a role. Among the cyclodextrins investigated, α-CD had most prominent effect on the perturbation of the ordered structures of the PCDA vesicles. Solid precipitates, formed by the PCDA vesicles in the presence of α-CD were shown to be PCDA - α-CD inclusion complexes by using DSC, FTIR and 1H NMR analysis. The results of studies using 4-nitrophenol as an inhibitor and the consideration of inner and outer diameters of cyclodextrins have led to the conclusion that the color induced by the cyclodextrins is due to the formation of inclusion complexes with the polydiacetylene. Photograph of the polydiacetylene liposomes after 1 h in the presence of 10 mM of the three different cyclodextrins in a HEPES buffer solution.