p-dimethylaminobenzonitrile (DMABN), a typical dual fluorescent flurophor (TICTflurophore), was used as fluorescent probe. The microenviromental property of twelve methyl modified β-cyclodextrin(methyl β-CD) was com...p-dimethylaminobenzonitrile (DMABN), a typical dual fluorescent flurophor (TICTflurophore), was used as fluorescent probe. The microenviromental property of twelve methyl modified β-cyclodextrin(methyl β-CD) was compared with that of β-cyclodextrin (β-CD). Results showed that the polarity of the cavity of methyl β-CD is lower than that of β- CD, and the capacity of methyl β-CD inclusion with DMABN is stronger than that of β-CD inclusion with DMABN.展开更多
β-cyclodextrin (β-CD) induced aggregation and micelle formation of cetyltrimethylam-mnium broAnde (CTMAB) in aqueous solution is demonstrated by the dual fluorescence of p-N, N-dAnethyladrinobenzoic acid (DMABOA) ty...β-cyclodextrin (β-CD) induced aggregation and micelle formation of cetyltrimethylam-mnium broAnde (CTMAB) in aqueous solution is demonstrated by the dual fluorescence of p-N, N-dAnethyladrinobenzoic acid (DMABOA) typical of the twisted intramolecular charge transfer (TICT). The locally excited (LE) state of DMABOA is proved to have the characteristic of intramolecular charge transfer (ICT) with a polarity higher than that of ground state but lower than that of TICT state. The peak positions of the two fluorescence bands and theiI intensity ratio are employed to probe the interaction of β-CD with CTMAB. It is conc1uded that β-CD induces CTMAB aggregation as well as Ancelle formation and may change Ancelle structure. The results also indicate that TICT in aqueous solution may be affected by the anisotropy or viscosity of the medium,increasing viscosity disadvantaging the TICT process.展开更多
The unique structure of fluorescent proteins in which the fluorophore is encapsulated by the protein shell to restrict rotation and emit light inspired the screening of chromophores that selectively bind to biomolecul...The unique structure of fluorescent proteins in which the fluorophore is encapsulated by the protein shell to restrict rotation and emit light inspired the screening of chromophores that selectively bind to biomolecules to generate fluorescence. In this paper, we report a curcuminoid-BF2-like fluorescent dye NBF2containing 4-dimethylaniline as an electron-donating group. When this dye is combined with HSA or BSA, the fluorescence is enhanced 90/112-fold, and the fluorescence quantum yield increases from <0.001to 0.16/0.19. Such a large change in fluorescence enhancement is due to the encapsulation of N-BF2in the protein cavity by HSA/BSA, which inhibits the intramolecular rotation of the aniline moiety caused by charge transfer after the fluorophore is excited by light. N-BF2has fast and strong binding to HSA or BSA and was found to be reversible in solution and intracellularly. Since N-BF2also has the ability to target lipid droplets, the complex of N-BF2/HSA realizes the regulation of reversible lipid droplet staining in cells.展开更多
The microenvironmental effects of β-cyclodextrin (β-CD) on the twisted intramolecular charge transfer (TICT) of ρ-N, N-dimethylaminobenzaldehyde (DMABA) are investigated using fluorescence spectroscopy. The typical...The microenvironmental effects of β-cyclodextrin (β-CD) on the twisted intramolecular charge transfer (TICT) of ρ-N, N-dimethylaminobenzaldehyde (DMABA) are investigated using fluorescence spectroscopy. The typical TICT dual fluorescence of DMABA is observed in pure water and aqueous β-CD solution, and β-CD has s remarkable influence on the TICT fluorescence characteristics of DMABA. A linear dependence of the ratio of intensity of TICT fluorescence band (a band) to that of normal fluorescence band (b band) on DMABA concentration is also observed and the introduction of β-CD increases the linear slope. Combined with the results of absorption spectroscopy, fluorescence polarization, and peculiar salt effects, the properties of TICT state of DMABA, the interaction of DMABA with β-CD, and the intrinsic traits of the microenvironmental effects of β-CD are discussed in detail.展开更多
文摘p-dimethylaminobenzonitrile (DMABN), a typical dual fluorescent flurophor (TICTflurophore), was used as fluorescent probe. The microenviromental property of twelve methyl modified β-cyclodextrin(methyl β-CD) was compared with that of β-cyclodextrin (β-CD). Results showed that the polarity of the cavity of methyl β-CD is lower than that of β- CD, and the capacity of methyl β-CD inclusion with DMABN is stronger than that of β-CD inclusion with DMABN.
文摘β-cyclodextrin (β-CD) induced aggregation and micelle formation of cetyltrimethylam-mnium broAnde (CTMAB) in aqueous solution is demonstrated by the dual fluorescence of p-N, N-dAnethyladrinobenzoic acid (DMABOA) typical of the twisted intramolecular charge transfer (TICT). The locally excited (LE) state of DMABOA is proved to have the characteristic of intramolecular charge transfer (ICT) with a polarity higher than that of ground state but lower than that of TICT state. The peak positions of the two fluorescence bands and theiI intensity ratio are employed to probe the interaction of β-CD with CTMAB. It is conc1uded that β-CD induces CTMAB aggregation as well as Ancelle formation and may change Ancelle structure. The results also indicate that TICT in aqueous solution may be affected by the anisotropy or viscosity of the medium,increasing viscosity disadvantaging the TICT process.
基金supported by the National Natural Science Foundation of China (Nos. 22078314, 21878286, 21908216, 22078201, U1908202)。
文摘The unique structure of fluorescent proteins in which the fluorophore is encapsulated by the protein shell to restrict rotation and emit light inspired the screening of chromophores that selectively bind to biomolecules to generate fluorescence. In this paper, we report a curcuminoid-BF2-like fluorescent dye NBF2containing 4-dimethylaniline as an electron-donating group. When this dye is combined with HSA or BSA, the fluorescence is enhanced 90/112-fold, and the fluorescence quantum yield increases from <0.001to 0.16/0.19. Such a large change in fluorescence enhancement is due to the encapsulation of N-BF2in the protein cavity by HSA/BSA, which inhibits the intramolecular rotation of the aniline moiety caused by charge transfer after the fluorophore is excited by light. N-BF2has fast and strong binding to HSA or BSA and was found to be reversible in solution and intracellularly. Since N-BF2also has the ability to target lipid droplets, the complex of N-BF2/HSA realizes the regulation of reversible lipid droplet staining in cells.
基金Project supported by the Natural Science Foundation of Fujian Province, China.
文摘The microenvironmental effects of β-cyclodextrin (β-CD) on the twisted intramolecular charge transfer (TICT) of ρ-N, N-dimethylaminobenzaldehyde (DMABA) are investigated using fluorescence spectroscopy. The typical TICT dual fluorescence of DMABA is observed in pure water and aqueous β-CD solution, and β-CD has s remarkable influence on the TICT fluorescence characteristics of DMABA. A linear dependence of the ratio of intensity of TICT fluorescence band (a band) to that of normal fluorescence band (b band) on DMABA concentration is also observed and the introduction of β-CD increases the linear slope. Combined with the results of absorption spectroscopy, fluorescence polarization, and peculiar salt effects, the properties of TICT state of DMABA, the interaction of DMABA with β-CD, and the intrinsic traits of the microenvironmental effects of β-CD are discussed in detail.
