- Target-activated coumarin phototriggers specifically switch on fluorescence and photocleavage upon bonding to thiol-bearing protein
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A new concept in which only the molecular target, such as a thiol-bearing protein, can activate the phototrigger has been demonstrated. Such target-activatable phototriggers comprise three parts: a 7-aminocoumarin phototrigger, an electron acceptor (maleimide) that efficiently quenches the coumarin excited state, and a caged leaving group attached to the coumarin. In the absence of mercaptans, photoinduced electron transfer between coumarin and maleimide effectively blocks both the fluorescence and photocleavage pathways. Thiol-bearing molecules, however, readily annihilate the electron acceptor and thus restore the phototrigger for photorelease of the caged cargo (e.g., biotin). Unlike traditional phototriggers, functional-group-activated phototriggers allow easy handling under ambient light, report specific bonding to the target, and enable photocleavage capability selectively at the binding site in situ, thus effectively positioning the photoreleased cargo at the target. Meanwhile, the unique feature of thiol-specific activation of the fluorescence and photocleavage make our new phototrigger a universal tool that can be used to identify accurately protein cysteine S-nitrosylation, a physiologically important posttranslational modification.
- Lin, Qiuning,Bao, Chunyan,Cheng, Shuiyu,Yang, Yunlong,Ji, Wei,Zhu, Linyong
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- Quintuple stimuli-responsive nano-carrier with imaging function and preparation method of quintuple stimuli-responsive nano-carrier
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The invention discloses a quintuple stimuli-responsive nano-carrier with an imaging function and a preparation method of the quintuple stimuli-responsive nano-carrier. According to the nano-carrier, with rare earth up-conversion luminescent nanocrystal as a core and mesoporous silica as a shell, a hollow bell structure is constructed, the surface of the hollow bell structure is modified with an aminocoumarin light plate machine and a supramolecular nano-valve based on pillar arene, and an anti-cancer drug is loaded in a hollow cavity of mesoporous silica. The nano-carrier disclosed by the invention can respond to five external stimuli including acidity, alkalinity, zinc ions, electric potential and near-infrared light, causes configuration change or breakage of surface groups, then releases anti-cancer drugs, has fluorescence imaging and magnetic resonance imaging functions, and has an application prospect in the field of drug controlled release.
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- 7-Amino coumarin based fluorescent phototriggers coupled with nano/bio-conjugated bonds: Synthesis, labeling and photorelease
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By several synthetic pathways, we designed and synthesized a new series of unsymmetrical substituted 7-amino coumarin-based phototriggers with various nano/bio-conjugated bonds. The photophysical properties of most of the substituted coumarin-based phototriggers, except for compound P9 with maleimide group, showed no significant change compared with that of 7-(diethylamino)-4- (hydroxylmethyl) coumarin (DEACM-OH, the reported symmetric substituted 7-amine coumarin based phototrigger). Four compounds (P2, P4, P9, 14) were successfully conjugated with typical carriers such as mesoporous silica nanoparticles, biocompatible polymer PEG and common protein BSA, respectively. The efficient photorelease of ibuprofen (IBU) in the model cargo delivery system of MD4 confirmed that our designed phototriggers could serve well as a photo-cage for bioactive molecules and the release can be regulated precisely by manipulating the external irradiation conditions. All the results hinted at the superiority of using these coumarin functional compounds for photo-regulated release in biotechnology and biomedical areas. The Royal Society of Chemistry 2012.
- Lin, Qiuning,Bao, Chunyan,Fan, Guanshui,Cheng, Shuiyu,Liu, Hui,Liu, Zhenzhen,Zhu, Linyong
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p. 6680 - 6688
(2012/07/28)
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- Non-conjugated dendrimers with a porphyrin core and coumarin chromophores as peripheral units: Synthesis and photophysical properties
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Three porphyrin-cored dendrimers with non-conjugated coumarins as dendrons have been synthesized and characterized. The photophysical properties of the title compounds were investigated by means of UV/Vis absorption and fluorescence spectroscopy in dilute CH2Cl2 solutions and in thin neat films. The intramolecular energy transfer from the coumarin units to the porphyrin core clearly reveals two factors influencing energy-transfer efficiency. Firstly, a better spectral overlap between the absorption spectrum of porphyrin core and the emission spectrum of the coumarin moiety results in high energy-transfer efficiency. Secondly, a long alkyl side-chain improves solubility of dendrimers, but also prevents the coumarins from self-quenching. Hence, the dendrimer with N-octyl groups possesses a higher efficiency than that with N-ethyl groups. The dendrimers emit red light with higher fluorescence quantum yields over the free porphyrin.
- Mao, Mao,Song, Qin-Hua
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p. 975 - 981
(2012/03/27)
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