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91.
In the past decade, polymer vesicles prepared by self‐assembly techniques have attracted increasing scientific interest based on their unique features highlighted with tunable membrane properties, versatility, stability, and capacity of transporting hydrophilic as well as hydrophobic species. Polymersomes exhibit intriguing potential applications such as cell mimicking dimensions and functions, tunable delivery vehicles, for the templating of biomineralization, nanoreactors, and as scaffolds for biological conjugation. In this Feature Article, an overview of the preparation and application of recently developed “smart” polymer vesicles, which can respond to the novel external stimuli, including carbon dioxide (CO2), electrochemical potential, ultrasound, enzyme, near‐infrared light, and magnetic field is given. The response mechanism and morphology change are explored with specific focus on the functionalization of various domains of the polymer vesicles. In addition, the current limitations are explored as well as the challenges facing the development of these nanostructures toward real‐world applications.
92.
93.
赖氨酸在甘草次酸弹性囊泡形成过程中的作用机制 总被引:1,自引:0,他引:1
制备和评价含赖氨酸的甘草次酸弹性囊泡, 并考察赖氨酸在囊泡形成过程中的作用机制. 在水合介质中加入赖氨酸, 利用薄膜-高压均质法制备甘草次酸弹性囊泡. 并合成了甘草次酸赖氨酸盐及其弹性囊泡作为对比制剂. 通过对粒径、zeta电位、包封率、相转变温度、变形性和体外经皮渗透性的测试, 考察赖氨酸在甘草次酸弹性囊泡中的存在形式及作用. 结果显示加入赖氨酸后, 甘草次酸弹性囊泡的粒径略有降低, 膜相转变温度降低, 包封率和囊泡变形性显著提高, 载药量提高近30倍(1.5 mg·mL-1), 并显著高于其赖氨酸盐所形成囊泡的载药量和弹性. 此外, 赖氨酸的加入使弹性囊泡的变形能力增加, 8 h累积透过量和皮肤驻留量分别提高4.3倍和9.2倍. 表明赖氨酸与甘草次酸形成离子缔合物, 促进甘草次酸参与膜的形成, 使膜的流动性增加, 赖氨酸与弹性囊泡对提高囊泡载药量起协同作用. 相似文献
94.
Greater stability of liposome coatings and improved resolution of model steroids in capillary electrochromatography (CEC) were sought by adding small diamines (ethylenediamine, diaminopropane, bis-tris-propane, or N-(2-hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid, HEPES)) to the liposome solution before coating of fused silica capillaries. The phospholipid coatings consisted of 1 mM of 8:2 mol% phosphatidylcholine (PC)/phosphatidylserine (PS) and 5 mM of modifier in buffer solutions (acetate, phosphate, or Tris) at pH 4.0-7.4. The coating was based on a published procedure, and five steroids were used as neutral model analytes in evaluation of the coating. The results showed that under optimal conditions, the small linear diamines increased the packing density of anionic phospholipids, leading to improved separations. In addition, the choice of buffer for the liposome coating and separation appeared to influence the performance of the coatings. While buffers with amino groups take part in the phospholipid bilayer formation, buffers like phosphate may even have negative effect on coating formation. The factors affecting phospholipid coatings with diamines as modifiers are clarified. 相似文献
95.
Su Xiang WEI Ying LI Kong Shuang ZHAO* Department of Chemistry South China Normal University Guangzhou 《中国化学快报》2001,(1)
IntroductionWhen the cationic and anionic surfactants in which the total carbon number is equal to or greater than 20 are mixed, then the vesicles can form spontaneously due to the strong interactions or by sonication1. Vesicle is of bilayer structure containing a closed aqueous room, resembling the structure of a real cell. So it seems to be imperative to study the membrane mimicry system like vesicle in order to understand the structure and functions of real cells further. In addition, it ca… 相似文献
96.
Y. Kawasaki A. Kuboki S. Ohira M. Kodama 《Journal of Thermal Analysis and Calorimetry》2006,85(3):609-616
Hydration
properties of lipid bilayer systems are compared for symmetric chain sphingomyelin
(N-palmitoylsphingomyelin) and asymmetric chain sphingomyelin (N-lignoceroylsphingomyelin).
These sphingomyelins were semisynthesized by a deacylation- reacylation process
with a natural sphingomyelin used as a starting material. The number of differently
bound water molecules was estimated by a deconvolution analysis of the ice-melting
curves obtained by a differential scanning calorimetry (DSC) and was used
to construct a water distribution diagram for these water molecules. Similarly
to a natural sphingomyelin used for comparison, the asymmetric chain sphingomyelin
was found to form small size vesicles having an internal cavity and incorporate
15 water molecules per molecule of lipid into its cavity, in contrast with
5 H2O/lipid for freezable interlamellar water observed
for large size multilamellar vesicles formed by the symmetric chain sphingomyelin. 相似文献
97.
Synaptic vesicles are organelles of the nerve terminal that secrete neurotransmitters by fusion with the presynaptic plasma membrane. Vesicle fusion is tightly controlled by depolarization of the plasma membrane and a set of proteins that may undergo post-translational modifications such as phosphorylation. In order to identify proteins that undergo modifications as a result of synaptic activation, we induced massive exocytosis and analysed the synaptic vesicle compartment by benzyldimethyl-n-hexadecylammonium chloride (BAC)/SDS-PAGE and difference gel electrophoresis (DIGE) followed by MALDI-TOF-MS. We identified eight proteins that revealed significant changes in abundance following nerve terminal depolarization. Of these, six were increased and two were decreased in abundance. Three of these proteins were phosphorylated as detected by Western blot analysis. In addition, we identified an unknown synaptic vesicle protein whose abundance increased on synaptic activation. Our results demonstrate that depolarization of the presynaptic compartment induces changes in the abundance of synaptic vesicle proteins and post-translational protein modification. 相似文献
98.
99.
In recent years, there has been immense interest in studying nanoscale aggregate structures derived from various polydiacetylenes (PDAs). The motivation for this is not only to understand the fundamental aggregate structures at different scales, but also to explore their potential for future technological applications. PDAs have been made sensitive to external stimuli such as light and chemical entities by incorporating a spectroscopically active moiety or a receptor unit as the head group of the PDA molecule. This makes them suitable for applications such as sensing and actuating. Furthermore, owing to the delocalization of π‐conjugated electrons, PDAs have been exploited as good candidates for organic nonlinear optical materials. This Focus Review highlights some of the instructive work done by various groups to develop well‐defined one‐dimensional assembly systems with a highly structural aspect ratio, which can be directly imaged by microscopic techniques. 相似文献
100.
Yamaguchi A Nakano M Nochi K Yamashita T Morita K Teramae N 《Analytical and bioanalytical chemistry》2006,386(3):627-632
The adsorption and longitudinal diffusion behaviors of a series of hemicyanine dyes to phospholipid vesicle membranes were
studied by second-harmonic generation (SHG) and fluorescence spectroscopies. It was observed that the longitudinal diffusion
of cationic hemicyanine dyes takes place immediately after the initial adsorption of these dyes to the outer surface of the
vesicle membrane. In contrast, hardly any amount of a zwitterionic hemicyanine dye with a sulfonate group diffused across
the vesicle membrane within the measurement time (<2000 s). Based on the difference in the time-course responses of SHG and
fluorescence spectroscopies for all of the hemicyanine dyes tested, we propose that hydration of the sulfonate group is mainly
responsible for the low diffusivity of the zwitterionic hemicyanine dye. 相似文献