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Photochemical and photophysical properties of carotenoid immobilized on a surfactant micellar medium including chlorophyll as an artificial photosynthesis system

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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-a and b (MgChl-a and b) (Cro/MgChl), and its photophysical properties were studied using UV-vis absorption and fluorescence spectroscopy. The fluorescence of MgChl-a and b was 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-a and b occurs. The photostability of MgChl-a and b in 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/b in Cro/MgChl on irradiation is suppressed by the crocetin molecule on the surface of micelles.

No MeSH data available.


UV-vis absorption spectra of Cro/MgChl (solid line), MgChl-a/b (dashed line), and crocetin (dotted line) solution in the presence of CTAB micelles. The inset is the excitation spectrum of Cro/MgChl monitored at 670 nm.
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f2-2_57: UV-vis absorption spectra of Cro/MgChl (solid line), MgChl-a/b (dashed line), and crocetin (dotted line) solution in the presence of CTAB micelles. The inset is the excitation spectrum of Cro/MgChl monitored at 670 nm.

Mentions: Figure 2 shows the UV-vis absorption spectra of Cro/MgChl (solid line), MgChl-a/b (dashed line), and crocetin (dotted line) solution in the presence of CTAB micelles. The inset is the excitation spectrum of Cro/MgChl monitored at 670 nm. From UV-vis absorption spectrum measurement, the absorption maxima of Cro/MgChl were 407, 536, 670, and 740 nm. The absorption bands at 407, 670, and 740 nm were attributed to MgChl-a and b. The absorption band at 740 nm was due to the aggregation of MgChl-a and b molecules. The small absorption band at 536 nm due to crocetin was observed in Cro/MgChl. The shape of the absorption spectrum of Cro/MgChl is similar to that on the summation of the spectra of MgChl-a/b and crocetin. This result shows no electrostatic interaction among crocetin, and MgChl-a and b in Cro/MgChl at a ground state.


Photochemical and photophysical properties of carotenoid immobilized on a surfactant micellar medium including chlorophyll as an artificial photosynthesis system
UV-vis absorption spectra of Cro/MgChl (solid line), MgChl-a/b (dashed line), and crocetin (dotted line) solution in the presence of CTAB micelles. The inset is the excitation spectrum of Cro/MgChl monitored at 670 nm.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC5036646&req=5

f2-2_57: UV-vis absorption spectra of Cro/MgChl (solid line), MgChl-a/b (dashed line), and crocetin (dotted line) solution in the presence of CTAB micelles. The inset is the excitation spectrum of Cro/MgChl monitored at 670 nm.
Mentions: Figure 2 shows the UV-vis absorption spectra of Cro/MgChl (solid line), MgChl-a/b (dashed line), and crocetin (dotted line) solution in the presence of CTAB micelles. The inset is the excitation spectrum of Cro/MgChl monitored at 670 nm. From UV-vis absorption spectrum measurement, the absorption maxima of Cro/MgChl were 407, 536, 670, and 740 nm. The absorption bands at 407, 670, and 740 nm were attributed to MgChl-a and b. The absorption band at 740 nm was due to the aggregation of MgChl-a and b molecules. The small absorption band at 536 nm due to crocetin was observed in Cro/MgChl. The shape of the absorption spectrum of Cro/MgChl is similar to that on the summation of the spectra of MgChl-a/b and crocetin. This result shows no electrostatic interaction among crocetin, and MgChl-a and b in Cro/MgChl at a ground state.

View Article: PubMed Central - PubMed

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-a and b (MgChl-a and b) (Cro/MgChl), and its photophysical properties were studied using UV-vis absorption and fluorescence spectroscopy. The fluorescence of MgChl-a and b was 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-a and b occurs. The photostability of MgChl-a and b in 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/b in Cro/MgChl on irradiation is suppressed by the crocetin molecule on the surface of micelles.

No MeSH data available.