排序方式: 共有165条查询结果,搜索用时 15 毫秒
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Zhiyong Liu Tianye Cao Yudong Xue Mengting Li Mengsi Wu Prof. Jonathan W. Engle Prof. Qianjun He Prof. Weibo Cai Prof. Minbo Lan Prof. Weian Zhang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(9):3740-3746
Nanocarriers are employed to deliver photosensitizers for photodynamic therapy (PDT) through the enhanced penetration and retention effect, but disadvantages including the premature leakage and non-selective release of photosensitizers still exist. Herein, we report a 1O2-responsive block copolymer (POEGMA-b-P(MAA-co-VSPpaMA) to enhance PDT via the controllable release of photosensitizers. Once nanoparticles formed by the block copolymer have accumulated in a tumor and have been taken up by cancer cells, pyropheophorbide a (Ppa) could be controllably released by singlet oxygen (1O2) generated by light irradiation, enhancing the photosensitization. This was demonstrated by confocal laser scanning microscopy and in vivo fluorescence imaging. The 1O2-responsiveness of POEGMA-b-P(MAA-co-VSPpaMA) block copolymer enabled the realization of self-amplified photodynamic therapy by the regulation of Ppa release using NIR illumination. This may provide a new insight into the design of precise PDT. 相似文献
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Qi‐Zhi Zhong Shiyao Li Jingqu Chen Ke Xie Shuaijun Pan Joseph J. Richardson Frank Caruso 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(36):12693-12698
The tunable growth of metal–organic materials has implications for engineering particles and surfaces for diverse applications. Specifically, controlling the self‐assembly of metal–phenolic networks (MPNs), an emerging class of metal–organic materials, is challenging, as previous studies suggest that growth often terminates through kinetic trapping. Herein, kinetic strategies were used to temporally and spatially control MPN growth by promoting self‐correction of the coordinating building blocks through oxidation‐mediated MPN assembly. The formation and growth mechanisms were investigated and used to engineer films with microporous structures and continuous gradients. Moreover, reactive oxygen species generated by ultrasonication expedite oxidation and result in faster (ca. 30 times) film growth than that achieved by other MPN assembly methods. This study expands our understanding of metal–phenolic chemistry towards engineering metal–phenolic materials for various applications. 相似文献
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Andr K. Eckhardt Alexandre Bergantini Santosh K. Singh Peter R. Schreiner Ralf I. Kaiser 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(17):5719-5723
With nearly 200 molecules detected in interstellar and circumstellar environments, the identification of the biologically relevant α‐keto carboxylic acid, glyoxylic acid (HCOCOOH), is still elusive. Herein, the formation of glyoxylic acid via cosmic‐ray driven, non‐equilibrium chemistry in polar interstellar ices of carbon monoxide (CO) and water (H2O) at 5 K via barrierless recombination of formyl (HCO) and hydroxycarbonyl radicals (HOCO) is reported. In temperature‐programmed desorption experiments, the subliming neutral molecules were selectively photoionized and identified based on the ionization energy and distinct mass‐to‐charge ratios in combination with isotopically labeled experiments exploiting reflectron time‐of‐flight mass spectrometry. These studies unravel a key reaction path to glyoxylic acid, an organic molecule formed in interstellar ices before subliming in star‐forming regions like SgrB2(N), thus providing a critical entry point to prebiotic organic synthesis. 相似文献
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Caroline C. Womack Kyle N. Crabtree Laura McCaslin Oscar Martinez Robert W. Field John F. Stanton Michael C. McCarthy 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(16):4173-4176
Carbenes are reactive molecules of the form R1 C̈ R2 that play a role in topics ranging from organic synthesis to gas‐phase oxidation chemistry. We report the first experimental structure determination of dihydroxycarbene (HO C̈ OH), one of the smallest stable singlet carbenes, using a combination of microwave rotational spectroscopy and high‐level coupled‐cluster calculations. The semi‐experimental equilibrium structure derived from five isotopic variants of HO C̈ OH contains two very short CO single bonds (ca. 1.32 Å). Detection of HO C̈ OH in the gas phase firmly establishes that it is stable to isomerization, yet it has been underrepresented in discussions of the CH2O2 chemical system and its atmospherically relevant isomers: formic acid and the Criegee intermediate CH2OO. 相似文献
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