title: Photochemical and photophysical properties of carotenoid immobilized on a surfactant micellar medium including chlorophyll as an artificial photosynthesis system.
abstract: To develop an artificial photosynthesis model, the anionic water-soluble carotenoid dye crocetin was electrostatically immobilized onto the surface of cationic surfactant cetyltrimethylammonium bromide (CTAB) micellar medium including Mg chlorophyll-aandb(MgChl-aandb) (Cro/MgChl), and its photophysical properties were studied using UV-vis absorption and fluorescence spectroscopy. The fluorescence of MgChl-aandbwas observed, with the excitation wavelength attributed to the absorption band of crocetin, indicating that photo-induced energy transfer from the photoexcited state of crocetin to MgChl-aandboccurs. The photostability of MgChl-aandbin Cro/MgChl was investigated under continuous irradiation. After 60 min irradiation, the absorbance decreases at 660 nm Cro/MgChl and MgChl-a/b, without crocetin, were 3.0 and 17%, respectively. These results indicate that the photo-bleaching rate of MgChl-a/bin Cro/MgChl on irradiation is suppressed by the crocetin molecule on the surface of micelles.
authors.affiliation: Department of Applied Chemistry, Oita University, Dannoharu 700, Oita 870-1192, Japan.
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Fuchino
authors.affiliation: Department of Applied Chemistry, Oita University, Dannoharu 700, Oita 870-1192, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Amao
keywords: Artificial photosynthesis; Carotenoid; Crocetin; Light-harvesting Mg chlorophyll-a, b; Photo-protection