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991.
Fan Xiao Lin Lin Zhicong Chao Chen Shao Zhe Chen Zixiang Wei Jingxiong Lu Yishun Huang Lanqing Li Quan Liu Yongye Liang Leilei Tian 《Angewandte Chemie (International ed. in English)》2020,59(24):9702-9710
DNA nanotechnology plays an increasingly important role in the biomedical field; however, its application in the design of organic nanomaterials is underexplored. Herein, we report the use of DNA nanotechnology to transport a NIR‐II‐emitting nanofluorophore across the blood–brain barrier (BBB), facilitating non‐invasive imaging of brain tumors. Specifically, the DNA block copolymer, PS‐b‐DNA, is synthesized through a solid‐phase click reaction. We demonstrate that its self‐assembled structure shows exceptional cluster effects, among which BBB‐crossing is the most notable. Therefore, PS‐b‐DNA is utilized as an amphiphilic matrix to fabricate a NIR‐II nanofluorephore, which is applied in in vivo bioimaging. Accordingly, the NIR‐II fluorescence signal of the DNA‐based nanofluorophore localized at a glioblastoma is 3.8‐fold higher than the NIR‐II fluorescence signal of the PEG‐based counterpart. The notably increased imaging resolution will significantly benefit the further diagnosis and therapy of brain tumors. 相似文献
992.
Xiangchuan Meng Zhi Xing Xiaotian Hu Zengqi Huang Ting Hu Licheng Tan Fengyu Li Yiwang Chen 《Angewandte Chemie (International ed. in English)》2020,59(38):16602-16608
Perovskite solar cells (PSCs) are a promising photovoltaic technology for stretchable applications because of their flexible, light‐weight, and low‐cost characteristics. However, the fragility of crystals and poor crystallinity of perovskite on stretchable substrates results in performance loss. In fact, grain boundary defects are the “Achilles’ heel” of optoelectronic and mechanical stability. We incorporate a self‐healing polyurethane (s‐PU) with dynamic oxime–carbamate bonds as a scaffold into the perovskite films, which simultaneously enhances crystallinity and passivates the grain boundary of the perovskite films. The stretchable PSCs with s‐PU deliver a stabilized efficiency of 19.15 % with negligible hysteresis, which is comparable to the performance on rigid substrates. The PSCs can maintain over 90 % of their initial efficiency after 3000 hours in air because of their self‐encapsulating structure. Importantly, the self‐healing function of the s‐PU scaffold was verified in situ. The s‐PU can release mechanical stress and repair cracks at the grain boundary on multiple levels. The devices recover 88 % of their original efficiency after 1000 cycles at 20 % stretch. We believe that this ingenious growth strategy for crystalline semiconductors will facilitate development of flexible and stretchable electronics. 相似文献
993.
Shengyun Huang Andrea Cel Erwin Adams Zdenk Glatz Ann Van Schepdael 《Journal of separation science》2020,43(17):3565-3572
Capillary electrophoresis is a modern separation technique characterized by many benefits, which qualify it also for enzyme assays and the study of enzyme kinetics during drug development. Homogeneous or heterogeneous approaches can be followed for the enzymatic incubation. In this study, an immobilization procedure of aldehyde oxidase on magnetic particles was developed considering their integration with capillary electrophoresis. A number of magnetic nano/microparticle types were tested for this purpose, showing that aldehyde oxidase was most active when immobilized on bare silica magnetic nanoparticles. Primarily, the reusability of the enzyme immobilized on bare silica nanoparticles was tested. Three consecutive incubations with substrate could be performed, but the activity considerably dropped after the first incubation. One reason could be an enzyme detachment from the nanoparticles, but no release was detected neither at 4°C nor at 37°C during 5 h. The drop in enzymatic activity observed in consecutive incubations, could also be due to inactivation of the enzyme over time at given temperature. For the immobilized enzyme stored at 4°C, the activity decreased to 83% after 5 h, in contrast with a steep decrease at 37°C to 37%. 相似文献
994.
Fabrication of Melamine/Tb3+-Intercalated Polydiacetylene Nanosheets and Their Thermochromic Reversibility 下载免费PDF全文
Polydiacetylene (PDA) is one kind of the conjugated polymer with layered structure, which can serve as a host to accommodate the guest components through intercalation. In these intercalated PDAs, some of them were reported to have a nearly perfect organized structure and perform completely reversible thermochromism. Till now, these reported intercalated PDAs were made by only introducing a single component for intercalation. Here, we chose 10, 12-pentacosadiynoic acid (PCDA) as the monomer, of which the carboxyl-terminal groups can interact with either Tb\begin{document}$ ^{3+} $\end{document} ions or melamines (MAs). When the feeding molar ratio of PCDA, MA, and Tb\begin{document}$ ^{3+} $\end{document} ion was 3:267:1, only Tb\begin{document}$ ^{3+} $\end{document} ions were intercalated though excess MAs existed. Such Tb\begin{document}$ ^{3+} $\end{document} -intercalated poly-PCDA exhibited completely reversible thermochromism, where almost all the carboxyl groups interacted with Tb\begin{document}$ ^{3+} $\end{document} ions to form the nearly perfect structure. When the feeding molar ratio of PCDA, MA, and Tb\begin{document}$ ^{3+} $\end{document} ion was 3:267:0.6, both Tb\begin{document}$ ^{3+} $\end{document} ions and MAs were intercalated. There existed some defects in the imperfect MA-intercalated domains and at the domain boundaries. The MA/Tb\begin{document}$ ^{3+} $\end{document} -intercalated poly-PCDA exhibits partially reversible thermochromism, where the backbones near the defects are hard to return the initial conformation, while the rest, those at nearly perfect organized domains, are still able to restore the initial conformation. 相似文献
995.
Kaikai Wen Lifen Wu Xiaoxi Wu Ying Lu Tao Duan Han Ma Aidong Peng Qinqin Shi Hui Huang 《Angewandte Chemie (International ed. in English)》2020,59(31):12756-12761
Cancer possesses normoxic and hypoxia microenvironments with different levels of oxygen, needing different efficacies of photothermal and photodynamic therapies. It is important to precisely tune the photothermal and photodynamic effects of phototherapy nano‐agents for efficient cancer treatment. Now, a series of copolymeric nanoparticles (PPy‐Te NPs) were synthesized in situ by controlled oxidative copolymerization with different ratios of pyrrole to tellurophene by FeCl3. The photothermal and photodynamic effects of semiconducting nano‐agents under the first near‐infrared (NIR) irradiation were precisely and systematically tuned upon simply varying the molar ratio of the pyrrole to tellurophene. The PPy‐Te NPs were used for cancer treatment in mice, exhibiting excellent biocompatibility and therapeutic effect. This work presents a simple method to tune photothermal and photodynamic therapies effect in semiconducting nano‐agents for cancer treatment. 相似文献
996.
Yixin Xie Yinzhi Fang Zhen Huang Amanda M. Tallon Christopher W. am Ende Joseph M. Fox 《Angewandte Chemie (International ed. in English)》2020,59(39):16967-16973
Since tetrazines are important tools to the field of bioorthogonal chemistry, there is a need for new approaches to synthesize unsymmetrical and 3‐monosubstituted tetrazines. Described here is a general, one‐pot method for converting (3‐methyloxetan‐3‐yl)methyl carboxylic esters into 3‐thiomethyltetrazines. These versatile intermediates were applied to the synthesis of unsymmetrical tetrazines through Pd‐catalyzed cross‐coupling and in the first catalytic thioether reduction to access monosubstituted tetrazines. This method enables the development of new tetrazine compounds possessing a favorable combination of kinetics, small size, and hydrophilicity. It was applied to a broad range of aliphatic and aromatic ester precursors and to the synthesis of heterocycles including BODIPY fluorophores and biotin. In addition, a series of tetrazine probes for monoacylglycerol lipase (MAGL) were synthesized and the most reactive one was applied to the labeling of endogenous MAGL in live cells. 相似文献
997.
Meng Su Feifei Qin Zeying Zhang Bingda Chen Qi Pan Zhandong Huang Zheren Cai Zhipeng Zhao Xiaotian Hu Dominique Derome Jan Carmeliet Yanlin Song 《Angewandte Chemie (International ed. in English)》2020,59(34):14234-14240
A key issue of micro/nano devices is how to integrate micro/nanostructures with specified chemical components onto various curved surfaces. Hydrodynamic printing of micro/nanostructures on three‐dimensional curved surfaces is achieved with a strategy that combines template‐induced hydrodynamic printing and self‐assembly of nanoparticles (NPs). Non‐lithography flexible wall‐shaped templates are replicated with microscale features by dicing a trench‐shaped silicon wafer. Arising from the capillary pumped function between the template and curved substrates, NPs in the colloidal suspension self‐assemble into close‐packed micro/nanostructures without a gravity effect. Theoretical analysis with the lattice Boltzmann model reveals the fundamental principles of the hydrodynamic assembly process. Spiral linear structures achieved by two kinds of fluorescent NPs show non‐interfering photoluminescence properties, while the waveguide and photoluminescence are confirmed in 3D curved space. The printed multiconstituent micro/nanostructures with single‐NP resolution may serve as a general platform for optoelectronics beyond flat surfaces. 相似文献
998.
Da‐Wei Fu Ji‐Xing Gao Wen‐Hui He Xue‐Qin Huang Yu‐Hua Liu Yong Ai 《Angewandte Chemie (International ed. in English)》2020,59(40):17477-17481
1,4‐Diazabicyclo[2.2.2]octane (dabco) and its derivatives have been extensively utilized as building units of excellent molecular ferroelectrics for decades. However, the homochiral dabco‐based ferroelectric remains a blank. Herein, by adding a methyl (Me) group accompanied by the introduction of homochirality to the [H2dabco]2+ in the non‐ferroelectric [H2dabco][TFSA]2 (TFSA=bis(trifluoromethylsulfonyl)ammonium), we successfully designed enantiomeric ferroelectrics [R and S‐2‐Me‐H2dabco][TFSA]2. The two enantiomers show two sequential phase transitions with transition temperature (Tc) as high as 405.8 K and 415.8 K, which is outstanding in both dabco‐based ferroelectrics and homochiral ferroelectrics. To our knowledge, [R and S‐2‐Me‐H2dabco][TFSA]2 are the first examples of dabco‐based homochiral ferroelectrics. This finding opens an avenue to construct dabco‐based homochiral ferroelectrics and will inspire the exploration of more eminent enantiomeric molecular ferroelectrics. 相似文献
999.
1000.
Danica L. Resuello Stephen B. Lirio Analin E. Porto Allan Patrick G. Macabeo Hsi-Ya Huang Mary Jho-Anne T. Corpuz 《Natural product research》2020,34(4):525-529
AbstractThe methanolic extract of Callyspongia samarensis (MCS) significantly inhibited β-secretase 1 (IC50 99.82?µg/mL) in a dose-dependent manner and demonstrated a noncompetitive type of inhibition. Furthermore, it exhibited the highest AMPK activation (EC50 14.47?μg/mL) as compared with the standard, Aspirin (EC50 >100?μg/mL). HPLC/ESI-MS analysis of MCS extract revealed 15 peaks, in which nine peaks demonstrated similar fragmentation pattern with the known compounds in literature and in database library: 5-aminopentanoic acid (1), 4-aminobutanoic acid (3), Luotonin A (4), (E)-3-(1H-imidazol-5-yl) prop-2-enoic acid (8), Galactosphingosine (10), D-sphingosine (11), 5,7,4′-trihydroxy-3′,5′-dimethoxyflavone (12), hydroxydihydrovolide (13), and 3,5-dibromo-4-methoxyphenylpyruvic acid (14); and 6 peaks are not identified (2, 5–7, 9, and 15). Acute oral toxicity test of MCS extract revealed that it is nontoxic, with an LD50 of >2000?mg/kg. Assessment of BBB permeability of MCS extract showed that compound 15 was able to cross the BBB making it a suitable candidate for developing CNS drugs. 相似文献