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排序方式: 共有1168条查询结果,搜索用时 343 毫秒
1.
《Biomaterials》2015
We propose a microfluidic system that generates nanovesicles (NVs) by slicing living cell membrane with microfabricated 500 nm-thick silicon nitride (SixNy) blades. Living cells were sliced by the blades while flowing through microchannels lined with the blades. Plasma membrane fragments sliced from the cells self-assembled into spherical NVs of ∼100–300 nm in diameter. During self-assembly, the plasma membrane fragments enveloped exogenous materials (here, polystyrene latex beads) from the buffer solution. About 30% of beads were encapsulated in NVs, and the generated NVs delivered the encapsulated beads across the plasma membrane of recipient cells, but bare beads could not penetrate the plasma membrane of recipient cells. This result implicates that the NVs generated using the method in this study can encapsulate and deliver exogenous materials to recipient cells, whereas exosomes secreted by cells can deliver only endogenous cellular materials. 相似文献
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Shuo Zhang Chunhua Cai Zhanwen Xu Jiaping Lin Xiao Jin 《Macromolecular chemistry and physics.》2019,220(3)
For block copolymer (BCP)/homopolymer self‐assembly systems, the molecular weight of homopolymers is usually lower than that of BCPs. Herein, the cooperative self‐assembly of polystyrene‐b‐poly(ethylene glycol) (PS‐b‐PEG) BCPs with high‐molecular‐weight polystyrene (PS) homopolymers is reported. The molecular weight of PS homopolymers is 3–63 times that of the PS blocks. Typically, a spherical micelle–vesicle–large sphere morphology transition is observed by increasing the weight fraction of PS homopolymers in the polymer mixtures (f HP). Dynamic process studies reveal that with adding water to the solution of polymer mixtures in organic solvent, the homopolymers first collapse into globules, and their size increases with f HP and the molecular weight. Then these PS globules cooperatively self‐assemble with the PS‐b‐PEG BCPs. Depending on their size, these PS globules play different roles in the self‐assembly process. Small PS globules act as morphology modifiers inducing the micelle–vesicle transition, while large PS globules serve as self‐assembly templates for PS‐b‐PEG resulting in large spheres. 相似文献
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Alberto Piloni Cheng Cao Christopher J. Garvey Andreas Walther Martina H. Stenzel 《Macromolecular chemistry and physics.》2019,220(20)
Poly(vinyl pyridine) has widely been used as a pH‐responsive polymer to trigger changes in self‐assembly of block copolymer micelles. However, the polymer is known to display toxic features, which limits its ultimate applicability for biological applications. Here, poly(4‐vinyl imidazole) (P4VIm), a much more biocompatible polymer, is used as a pH‐responsive block to modulate the self‐assembly of ABC triblock terpolymers. In this article, the synthesis of the poly(1‐acryloyl fructopyranose)‐block‐ poly(n‐butyl acrylate)‐block‐ poly(4‐vinyl imidazole) (PFruA52‐b‐PBuA300‐b‐P4VIm250) triblock terpolymers is first discussed by sequential reversible addition fragmentation chain transfer (RAFT) polymerization. Subsequently, the structure formation of the triblock terpolymer is elucidated by step‐wise solvent exchange. The polymer readily dissolves in methanol, but self‐assembles into micelles with PBuA cores and mixed shell in methanol–water mixtures. Solvent exchange against buffer solutions of pH 6–6.5 leads to collapse of P4VIm due to deprotonation and induces self‐assembly into caterpillar‐like non‐spherical nanoparticles, most likely via the formation of intermediate Janus particles. The rearrangement into larger hierarchical structure, as seen by small angle X‐ray scattering (SAXS), is found to process within several hours. The article is concluded by demonstrating lower cytotoxicity values for the present polymer in comparison to a structurally analogous triblock terpolymer based on poly(vinyl pyridine). 相似文献
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多糖作为生物界一种主要的细胞构造基元及重要的储能材料,在生命体中扮演着十分重要的角色,因其具有良好的生物相容性、亲水性、生物可降解性及配伍性,广泛被用于食品和药品。超分子是依靠分子间相互作用结合在一起的复杂的、有组织的聚集体,能保持一定的完整性并使其具有明确的微观结构和宏观特性。基于多糖组装的超分子作为天然大分子物质具有广泛的生物特性,文章就多糖经超分子组装后产生的体内外生物活性变化进行综述,以期为多糖的进一步扩大应用提供参考和理论支撑。 相似文献
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Fibronectin is a component of subendothelial matrices and abundant in plasma. A role of fibronectin in thrombogenesis has been suspected for three decades. Soluble fibronectin is assembled by adherent fibroblasts and platelets and thus converted to an insoluble form that mediates cell adhesion. Recently, in vivo studies using intravital videomicroscopy revealed that plasma fibronectin is important for stabilization of platelet aggregates after vascular injury. This review goes over roles of fibronectin in platelet functions with a focus on fibronectin assembly within developing platelet thrombi. 相似文献
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The seating mechanics of head‐neck modular tapers in vitro: Load‐displacement measurements,moisture, and rate effects 下载免费PDF全文
Eric S. Ouellette Aarti A. Shenoy Jeremy L. Gilbert 《Journal of orthopaedic research》2018,36(4):1164-1172
10.
NDUFAF3 variants that disrupt mitochondrial complex I assembly may associate with cavitating leukoencephalopathy 下载免费PDF全文
A. Ishiyama K. Muramatsu S. Uchino C. Sakai Y. Matsushima N. Makioka T. Ogata E. Suzuki H. Komaki M. Sasaki M. Mimaki Y.‐I. Goto I. Nishino 《Clinical genetics》2018,93(5):1103-1106
Genetic abnormalities in mitochondrial complex assembling factors are associated with leukoencephalopathy. We present a 1‐year‐old girl with consciousness disturbance after a respiratory infection. Brain MRI revealed leukoencephalopathy with bilaterally symmetrical hyperintensity in the substantia nigra, medial thalamic nuclei, and basal nuclei, as well as cavities in the cerebral white matter and corpus callosum. Lactate levels in the spinal fluid were high, while magnetic resonance spectroscopy of the cerebral white matter and basal nuclei showed high peak lactate levels, suggesting mitochondrial dysfunction. The respiratory enzyme activity of complex I was reduced to 17% to 21% in skeletal muscle. Whole exome sequencing identified compound heterozygous variations in NDUFAF3, involved in the assembly of mitochondrial complex I (c.342_343insGTG:p.117Valdup, c.505C > A:p.Pro169Thr). Two‐dimensional, blue‐native polyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulfate‐PAGE revealed reductions in Q‐module (NDUFS2, NDUFS3, and NDUFA9) and P‐module (NDUFB10 and NDUFB11) subunits, indicating disruption of mitochondrial complex I assembly. Our report expands the spectrum of clinical phenotypes associated with pathogenic variants of NDUFAF3. 相似文献