| Project/Area Number |
15350086
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Functional materials chemistry
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| Research Institution | Graduate School of Biomedical Sciences, Nagasaki University |
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Principal Investigator |
DE-QI Yuan Nagasaki University, Graduate School of Biomedical Sciences, Associate Professor, 大学院・医歯薬学総合研究科, 助教授 (70304962)
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| Project Period (FY) |
2003 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥15,000,000 (Direct Cost: ¥15,000,000)
Fiscal Year 2005: ¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 2004: ¥4,200,000 (Direct Cost: ¥4,200,000)
Fiscal Year 2003: ¥8,100,000 (Direct Cost: ¥8,100,000)
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| Keywords | Cyclodextrins / Chemiluminescence / Energy Transfer / Supramolecule / Molecular Recognition |
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| Research Abstract |
This research project aims at developing novel supramolecular methodologies to improve the light outputs of chemiluminescence (CL) reactions. Enzyme-like artificial catalysts are used to pre-organize the various reactants of the CL reaction of luminol in a supramolecular manner. An increase of ca. 40 folds in CL intensity has been observed when EDTA-bridged cyclodextrin (CD) dimer was used in the luminol reaction in the presence of Ce(IV) ion. It is clarified that the geometry of the dimers, cavity shape, surroundings of the metal ion, and the distance between the cavity and metal ion play very important role in increasing the CL outputs.
Oxalate reacts with H_2O_2 to release chemical energy that can excite a nearby chromophore which illuminates during relaxation. Bisbenzimidazole-capped CDs were found to be much more efficient than fluorescein in harvesting the chemical energy of this reaction and a good consistence of total CL intensity with the binding ability was observed.
Various dy
… More
es such as fluorescein and so forth were immobilized onto CDs, and the resultant dye-CD conjugates were applied to the oxalate reaction. A maximum 160-fold increase in CL output was demonstrated by coumarin-CD conjugates, and 10-fold increase was displayed by pyrene-CD conjugates. Even fluorescein, which is very efficient in CL reaction, is still rendered 25-fold more efficient when it is conjugated to the 6-position of β-CD. It is revealed that the principal contribution of the CD moieties is to improve the transfer of chemical energy to the dye pigments.
Tetraphenylporphyrin-bridged CD tetramer showed 5 times stronger CL intensity than tetraphenylporphyrin, yet the CL can be quenched by steroidal species. Only 5μM chenodeoxycholic acid is enough to cause a half quenching of CL of the tetramer, yet this concentration increased to 160μM and 170μM for corticosterone and ursodeoxycholic acid, respectively, despite their close structural similarity.
These results strongly support our idea that immobilization of a chromophore to an appropriate binding site improves greatly their performance in CL reaction and thus suggests the possibility to design CL systems for a specific target molecule. Less
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