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81.
Charge Transfer Induces Formation of Stimuli‐Responsive,Chiral, Cohesive Vesicles‐on‐a‐String that Eventually Turn into a Hydrogel 下载免费PDF全文
A charge transfer (CT) mediated two‐component, multistimuli responsive supergelation involving a L ‐histidine‐appended pyrenyl derivative (PyHisOMe) as a donor and an asymmetric bolaamphiphilic naphthalene‐diimide (Asym‐NDI) derivative as an acceptor in a 2:1 mixture of H2O/MeOH was investigated. Asym‐NDI alone self‐assembled into pH‐responsive vesicular nanostructures in water. Excellent selectivity in CT gel formation was achieved in terms of choosing amino acid appended pyrenyl donor scaffolds. Circular dichroism and morphological studies suggested formation of chiral, interconnected vesicular assemblies resembling “pearls‐on‐a‐string” from these CT mixed stacks. XRD studies revealed the formation of monolayer lipid membranes from these CT mixed stacks that eventually led to the formation of individual vesicles. Strong cohesive forces among the interconnected vesicles originate from the protrusion of the oxyethylene chains from the surfaces of the chiral vesicles. 相似文献
82.
Tomoyuki TAKAHASHI 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2015,91(7):305-320
Classically, the basic concept of chemical synaptic transmission was established at the frog neuromuscular junction, and direct intracellular recordings from presynaptic terminals at the squid giant presynaptic terminal have further clarified principles of neurotransmitter release. More recently, whole-cell patch-camp recordings from the calyx of Held in rodent brainstem slices have extended the classical concept to mammalian synapses providing new insights into the mechanisms underlying strength and precision of neurotransmission and developmental changes therein. This review summarizes findings from our laboratory and others on these subjects, mainly at the calyx of Held, with a particular focus on precise, high-fidelity, fast neurotransmission. The mechanisms by which presynaptic terminals acquire strong, precise neurotransmission during postnatal development are also discussed. 相似文献
83.
Meiling Chen Meng Sun Lixiang Wang Xiaoya Liu 《Journal of Dispersion Science and Technology》2014,35(4):494-500
Five coarse-grained models were built for amphiphilic random copolymers. The self-assembly of amphiphilic random copolymers in selective solvent was investigated via dissipative particle dynamics simulations. The simulation results showed that the content of hydrophilic particles and the repulsive parameter between solvent and copolymer particles were two key factors of the vesicle formation. We report herein on how to control the self-assembled morphology evolution. The two mechanisms of vesicle formation from amphiphilic random copolymers are found through investigating the dynamic processes of vesicle formation, which is in accordance with the experiment and simulation results of amphiphilic block copolymer reported in the literature. 相似文献
84.
Feng Liu Ming-Yan Gu Zhong-Ni Wang 《Journal of Dispersion Science and Technology》2013,34(10):1442-1448
Spontaneous vesicles of dicetyl dimethyl ammonium chloride (DCDAC) and its mixture with sodium bis-(2-ethylhexyl) sulfosuccinate (AOT) are observed respectively in ethanol-water mixed solvents, which have been demonstrated by negative-staining transmission electric microscope (TEM) and atomic force microscope (AFM). Ethanol can promote the vesicle formation, especially to pure DCDAC surfactant system. The entrapment efficiency of the vesicles to all-trans retinoic acid (ATRA) was measured by the first order derivative spectrophotometry method. The entrapment efficiency of ATRA reaches 22% in 0.5 ethanol volume ratio solution when the concentration of DCDAC is 2.5 × 10?3 mol/L. In the same solvents, the entrapment efficiency could be as high as 62% in 1:9 (molar ratio) DCDAC/AOT mixtures when the total concentration of surfactants is 3.0 × 10?3 mol/L. 相似文献
85.
The exploration of intracellular vesicles plays crucial roles for neuronal activity assessment. Neurons at different growth stages may possess distinct neuronal activity, including vesicular content and release kinetics. Here, we monitored the vesicular content and its release kinetics in neurons at different growth stages by intracellular vesicle electrochemical cytometry. We found that the neurotransmitters content of vesicles changed to be increased and the vesicle release process became longer as the neurons grew. Further, we demonstrated that the vesicular adsorption and rupture modes changed from the dominant simple event to simple and complex event coexisting mode. We speculate that this work provides a new strategy for the neuronal activity assessment or real- time cell activity analysis. 相似文献
86.
《Ultrasonics sonochemistry》2014,21(4):1299-1304
It has been known for more than 40 years that vacuolate organisms can be induced to sediment with ultrasound. However, robust indicators are still needed to compare the efficacy of different treatments. A repeatable index is proposed that makes it possible to quantify the ultrasonic induced sedimentation. The procedure is used to monitor the long term sedimentation of Microcystis aeruginosa after sonication. Results reveal that the sedimentation process continues after gas vesicles have fully recovered, although at a slower rate. 相似文献
87.
本工作报道了第一例具有电化学氧化还原刺激响应性的Janus超支化超分子聚合物,研究了其自组装及响应性解组装的行为.通过阴离子开环聚合和阳离子开环聚合的方法,分别合成了以β-环糊精为中心的亲水超支化聚缩水甘油醚CD-g-HPG和末端为二茂铁的疏水超支化聚(3-乙基-3-羟甲基环氧丁烷)Fc-g-HBPO.两者通过Fc/CD之间的主客体包结络合作用,构筑了两亲性Janus超支化超分子聚合物HBPO-b-HPG.该聚合物在水中可以自组装形成囊泡.通过动态光散射(DLS)跟踪、2D-NOESY和循环伏安曲线表征了CD-g-HPG和Fc-g-HBPO之间的主客体包结络合作用,通过扫描电子显微镜(SEM)和透射电子显微镜(TEM)表征了囊泡结构.最后,研究了囊泡在电化学刺激下的解组装行为,同时也验证了囊泡在加热、加入主客体竞争分子和化学氧化下的稳定性. 相似文献
88.
Crystallographically characterized M2L4 type cationic Cu(II)‐metallacryptands [MC(X)] derived from a series of bis‐pyridyl‐bis‐urea ligands (LX; X = O, S, C) are self‐assembled to single‐layered vesicular aggregates in DMSO, DMSO/water, and DMSO/DMEM (biological media). One such vesicle is MC(O)‐vesicle that is demonstrated to be able to load and release (pH responsive) an anticancer drug, namely doxorubicin hydrochloride (DOX). DOX‐loaded MC(O)‐vesicle is also successfully transported within MDA‐MB‐231 cells—a highly aggressive human breast cancer cell line. Such self‐assembling behavior to form vesicular aggregates by metallacryptands (MCs) is hitherto unknown. 相似文献
89.
90.