排序方式: 共有147条查询结果,搜索用时 15 毫秒
51.
Jiandong Pang Dr. Caiping Liu Dr. Yougui Huang Prof. Mingyan Wu Prof. Feilong Jiang Prof. Daqiang Yuan Falu Hu Dr. Kongzhao Su Guoliang Liu Prof. Maochun Hong 《Angewandte Chemie (International ed. in English)》2016,55(26):7478-7482
We demonstrate that three flexible MOFs termed FJI‐H11‐R (FJI‐H=Hong's group in Fujian Institute of Research on the Structure of Matter, R=Me, Et, iPr) can reversibly respond to temperature and solvents via structural transformations, which can be visualized by in situ single‐crystal X‐ray snapshot analyses. FJI‐H11‐R exhibit colossal anisotropic thermal expansion, with a record‐high uniaxial positive thermal‐expansion coefficient of 653.2×10?6 K?1 observed in FJI‐H11‐Me. Additionally, large c‐axial shrinkage of 32.4 % is also observed during desolvation. The stimuli‐responsive mechanism reveals the structural evolutions are related to the rotations and deformations of the organic linkers. 相似文献
52.
Vasanthy Karmegam Sandun S. Kuruppu Chinthaka M. Udamulle Gedara Michael C. Biewer Mihaela C. Stefan 《Journal of polymer science. Part A, Polymer chemistry》2021,59(23):3040-3052
The self-assembly of functionalized polycaprolactone amphiphilic diblock copolymers is explored for carrier-mediated doxorubicin delivery for cancer treatment. In this report, functionalized polycaprolactone-based amphiphilic block copolymers with controlled branching architecture are investigated. Star-like copolymers, namely 4-arm and 6-arm poly(γ-benzyloxy-ε-caprolactone)-b-poly{γ-2-[2-(2-methoxyethoxy)ethoxy]ethoxy-ε-caprolactone} (PBCL-b-PMEEECL) were synthesized by living ring-opening block copolymerization (ROP) of γ-(2-benzyloxy)-ε-caprolactone and γ-2-[2-(2-methoxyethoxy)ethoxy]ethoxy-ε-caprolactone using multifunctional initiators. A systematic investigation of the effect of branching points on polymer properties and micellar carrier properties was carried out. The star-like PBCL-b-PMEEECL micelles displayed better thermodynamic stability, size reduction, and enhanced doxorubicin encapsulation than the linear PBCL-b-PMEEECL. Furthermore, the π–π stacking between the benzyl group of the hydrophobic PBCL core and the doxorubicin, the anti-cancer drug, also increases the stability and loading capacity of the micelles. The star-polymers display tunable thermoresponsivity in the range of 40–42°C. When the DOX-loaded micelles are accumulated in the tumor, the shell of the polymeric micelles dehydrates upon heating (at a temperature above its LCST), causing disassembling of the micelles and releasing of DOX. Compared with DOX-loaded linear and 4-arm micelles, DOX-loaded 6-arm micelles exhibited higher in vitro anti-tumor activity. Thus, the 6-arm benzyl substituted polycaprolactone-based micellar systems are promising candidates for drug delivery applications. 相似文献
53.
Dr. Gabriel Brunet Dr. Elizaveta A. Suturina Dr. Guillaume P. C. George Dr. Jeffrey S. Ovens Paul Richardson Dr. Christophe Bucher Prof. Muralee Murugesu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(69):16455-16462
Donor–acceptor interactions are ubiquitous in the design and understanding of host–guest complexes. Despite their non-covalent nature, they can readily dictate the self-assembly of complex architectures. Here, a photo-/redox-switchable metal–organic nanocapsule is presented, which was assembled by using lanthanide ions and viologen building blocks, by relying on such donor–acceptor interactions. The potential of this unique barrel-shaped structure is highlighted for the encapsulation of suitable electron donors, akin to the well-investigated “blue-box” macrocycles. The light-triggered reduction of the viologen units has been investigated by single-crystal-to-single-crystal X-ray diffraction experiments, complemented by magnetic, optical, and solid-state electrochemical characterizations. Density functional theory (DFT) calculations were employed to suggest the most likely electron donor in the light-triggered reduction of the viologen-based ligand. 相似文献
54.
Bernhard S. Birenheide Felix Krämer Lea Bayer Dr. Paul Mehlmann Prof. Dr. Fabian Dielmann Prof. Dr. Frank Breher 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(61):15067-15074
Novel multistimuli-responsive phosphine ligands comprising a redox-active [3]dioxaphosphaferrocenophane backbone and a P-bound imidazolin-2-ylidenamino entity that allows switching by protonation are reported. Investigation of the corresponding metal complexes and their redox behaviour are reported and show the sensitivity of the system towards protonation and metal coordination. The experimental findings are supported by DFT calculations. Protonation and oxidation events are applied in Rh-catalysed hydrosilylations and demonstrate a remarkable influence on reactivity and/or selectivity. 相似文献
55.
56.
Yin Wang Kearsley M. Dillon Zhao Li Ethan W. Winckler John B. Matson 《Angewandte Chemie (International ed. in English)》2020,59(38):16698-16704
Overproduction of superoxide anion (O2.?), the primary cellular reactive oxygen species (ROS), is implicated in various human diseases. To reduce cellular oxidative stress caused by overproduction of superoxide, we developed a compound that reacts with O2.? to release a persulfide (RSSH), a type of reactive sulfur species related to the gasotransmitter hydrogen sulfide (H2S). Termed SOPD‐NAC , this persulfide donor reacts specifically with O2.?, decomposing to generate N‐acetyl cysteine (NAC) persulfide. To enhance persulfide delivery to cells, we conjugated the SOPD motif to a short, self‐assembling peptide (Bz‐CFFE‐NH2) to make a superoxide‐responsive, persulfide‐donating peptide ( SOPD‐Pep ). Both SOPD‐NAC and SOPD‐Pep delivered persulfides/H2S to H9C2 cardiomyocytes and lowered ROS levels as confirmed by quantitative in vitro fluorescence imaging studies. Additional in vitro studies on RAW 264.7 macrophages showed that SOPD‐Pep mitigated toxicity induced by phorbol 12‐myristate 13‐acetate (PMA) more effectively than SOPD‐NAC and several control compounds, including common H2S donors. 相似文献
57.
DNA分子由于其独特的生物相容性和可编程性,在增强药物靶向性和降低药物毒性方面展现了独特的优势和巨大的潜力。随着人们对肿瘤微环境研究的深入和环境响应性的DNA触发器的研制,近些年已报道了许多基于肿瘤微环境响应的DNA纳米结构递药系统,这些DNA纳米结构递药系统结合了纳米运载工具良好的生物分布和药代动力学特性,以及小型药物载体的快速扩散和渗透特性。通过靶向广泛的肿瘤栖息地而不是肿瘤特异性受体,该策略有可能克服肿瘤异质性问题,并可用于设计诊断和治疗多种实体肿瘤的纳米颗粒。在体内能够稳定地转运,在肿瘤组织独特的微环境刺激下释放药物,能有效地控制药物释放部位和释放速度,极大地降低了肿瘤治疗的毒副作用。本文主要从pH响应型、GSH响应型、ATP响应型、酶响应型、抗原响应型五个方面,综述了基于肿瘤微环境响应的DNA纳米结构递药系统的最新研究进展,分类介绍了这些DNA纳米载体的设计策略和响应释放机制,此外,还重点介绍了该领域面临的前景和挑战。 相似文献
58.
Dr. Yin Wang Kearsley M. Dillon Zhao Li Ethan W. Winckler Prof. John B. Matson 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(38):16841-16847
Overproduction of superoxide anion (O2.−), the primary cellular reactive oxygen species (ROS), is implicated in various human diseases. To reduce cellular oxidative stress caused by overproduction of superoxide, we developed a compound that reacts with O2.− to release a persulfide (RSSH), a type of reactive sulfur species related to the gasotransmitter hydrogen sulfide (H2S). Termed SOPD-NAC , this persulfide donor reacts specifically with O2.−, decomposing to generate N-acetyl cysteine (NAC) persulfide. To enhance persulfide delivery to cells, we conjugated the SOPD motif to a short, self-assembling peptide (Bz-CFFE-NH2) to make a superoxide-responsive, persulfide-donating peptide ( SOPD-Pep ). Both SOPD-NAC and SOPD-Pep delivered persulfides/H2S to H9C2 cardiomyocytes and lowered ROS levels as confirmed by quantitative in vitro fluorescence imaging studies. Additional in vitro studies on RAW 264.7 macrophages showed that SOPD-Pep mitigated toxicity induced by phorbol 12-myristate 13-acetate (PMA) more effectively than SOPD-NAC and several control compounds, including common H2S donors. 相似文献
59.
Xiaolei Guo Nansong Zhu Shi-Ping Wang Prof. Guanghua Li Prof. Fu-Quan Bai Prof. Yi Li Prof. Yonghao Han Prof. Bo Zou Dr. Xiao-Bo Chen Prof. Zhan Shi Prof. Shouhua Feng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(44):19884-19889
Herein we report two new TPE-based 3D MOFs, that is, Sr-ETTB and Co-ETTB (TPE=Tetraphenylethylene, H8ETTB=4′,4′′′,4′′′′′,4′′′′′′′-(ethene-1,1,2,2-tetrayl)tetrakis(([1,1′-biphenyl]-3,5-dicarboxylic acid))). Through tailoring outer shell electron configurations of SrII and CoII cations, the fluorescence intensity of the MOFs is tuned from high emission to complete non-emission. Sr-ETTB with strong blue fluorescence shows reversible fluorescence variations in response to pressure and temperature, which is directly related to the reversible deformation of the crystal structure. In addition, non-emissive Co-ETTB counterpart exhibits a turn-on fluorescent enhancement under the stimulation of analyte histidine. In the process, TPE-cored linkers in the MOFs are released through competitive coordination substitution and subsequently reassembled to perform aggregation-induced luminescence behavior originated from the organic linkers. 相似文献
60.
Yubin Bao Jianfeng Huang Pengfei Xue Jibin Wang Chifei Wu 《Journal of Dispersion Science and Technology》2013,34(10):1459-1464
The pH-responsive polyelectrolyte, named poly(methyl vinyl ether-alt-maleic anhydride) (PVM/MA), was grafted onto the surface of carbon black (CB) by ultrasonically degraded method. The effect of pH on the dispersion of PVM/MA grafted CB in water and waterborne polyurethane (WPU) was studied. Particle size of PVM/MA grafted CB and its transmission electron microscope images showed the increasing of pH in the suspension of grafted CB easily causes the aggregates of grafted CB. Furthermore, scanning electron microscope images showed grafted CB had better dispersibility than that of untreated CB in WPU emulsion or corresponding solid composite. When grafted CB was neutralized in aqueous solution, the compatibility between PVM/MA grafted CB and WPU got poor. In addition, the dispersion of grafted CB in solid composite could be controlled through tuning the composite resistance. 相似文献