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Processes associated with ionic current rectification at a 2D-titanate nanosheet deposit on a microhole poly(ethylene terephthalate) substrate

Films of titanate nanosheets (approx. 1.8-nm layer thickness and 200-nm size) having a lamellar structure can form electrolyte-filled semi-permeable channels containing tetrabutylammonium cations. By evaporation of a colloidal solution, persistent deposits are readily formed with approx. 10-μm thickness on a 6-μm-thick poly(ethylene-terephthalate) (PET) substrate with a 20-μm diameter microhole.

Mechanically robust cationic cellulose nanofibril 3D scaffolds with tuneable biomimetic porosity for cell culture

3D foam scaffolds were produced in a "bottom-up" approach from lyophilised cationic cellulose nanofibril (CCNF) dispersions and emulsions (CCNF degree of substitution 23.0 ± 0.9%), using a directional freezing/lyophilisation approach, producing internal architectures ranging from aligned smooth walled micro channels, mimicking vascularised tissue, to pumice-like wall textures, reminiscent of poro

Nanostructure of the deep eutectic solvent/platinum electrode interface as a function of potential and water content

The interfacial nanostructure of the three most widely-studied Deep Eutectic Solvents (DESs), choline chloride:urea (ChCl:Urea), choline chloride:ethylene glycol (ChCl:EG), and choline chloride:glycerol (ChCl:Gly) at a Pt(111) electrode has been studied as a function of applied potential and water content up to 50 wt%. Contact mode atomic force microscope (AFM) force-distance curves reveal that fo

Understanding heat driven gelation of anionic cellulose nanofibrils : Combining saturation transfer difference (STD) NMR, small angle X-ray scattering (SAXS) and rheology

A novel mechanism of heat-triggered gelation for oxidised cellulose nanofibrils (OCNF) is reported. We demonstrate that a synergistic approach combining rheology, small-angle X-ray scattering (SAXS) and saturation transfer difference NMR (STD NMR) experiments enables a detailed characterisation of gelation at different length scales. OCNF dispersions experience an increase in solid-like behaviour

Alcohol induced gelation of TEMPO-oxidized cellulose nanofibril dispersions

Solvent-induced physical hydrogels of TEMPO-oxidized cellulose nanofibrils (OCNFs) were obtained from aqueous/alcoholic dispersions of fibrils in lower alcohols, namely, methanol, ethanol, 1-propanol and 2-propanol. The sol-gel transition occurs above a critical alcohol concentration of ca. 30 wt% for all alcohols tested. The rheological properties of the hydrogels depend on the nature of the alco

Codelivery of a cytotoxin and photosensitiser via a liposomal nanocarrier : A novel strategy for light-triggered cytosolic release

Endosomal entrapment is a key issue for the intracellular delivery of many nano-sized biotherapeutics to their cytosolic or nuclear targets. Photochemical internalisation (PCI) is a novel light-based solution that can be used to trigger the endosomal escape of a range of bioactive agents into the cytosol leading to improved efficacy in pre-clinical and clinical studies. PCI typically depends upon

Formation of ordered mesoporous thin films through templating

Pores in the size range 2.0-20 nm are considered mesopores. Using the sol-gel process and a catalog of surfactant molecules, thin films with ordered mesopores can be produced. Films formed by evaporation-induced self-assembly, growth from solution, and other methods such as vapor phase deposition and pulsed laser deposition are examined. The various patterns derived from these approaches are discu

Surfactant controlled zwitterionic cellulose nanofibril dispersions

Zwitterionic cellulose nanofibrils (ZCNFs) with an isoelectric point of 3.4 were obtained by grafting glycidyltrimethylammonium chloride onto TEMPO/NaBr/NaOCl-oxidised cellulose nanofibrils. The ZCNF aqueous dispersions were characterized via transmission electron microscopy, rheology and small angle neutron scattering, revealing a fibril-bundle structure with pronounced aggregation at pH 7. Surfa

Pickering emulsions stabilized by naturally derived or biodegradable particles

Emulsions are used widely in formulated consumer products, paints and coatings, foods, and pharmaceutical preparations to name just a few examples. Frequently surfactants are employed as emulsifiers, but the use of particles, including nanoparticles, can offer advantages. Naturally derived, or synthetic, particles that are biodegradable can reduce end-of-life environmental impact, while offering a

Model-dependent small-angle scattering for the study of complex organic materials

Background: Small-angle scattering (SAS) is a powerful technique capable of determining the sample averaged structure of systems within sizes ranging from 1 nm to ~500 nm. This is particularly useful when applied to the study of self-assembled organic systems. Objective: This review article introduces the method of model-dependent analysis of small angle scattering. Method: The underlying mathemat

An acid-compatible co-polymer for the solubilization of membranes and proteins into lipid bilayer-containing nanoparticles

The fundamental importance of membrane proteins in drug discovery has meant that membrane mimetic systems for studying membrane proteins are of increasing interest. One such system has been the amphipathic, negatively charged poly(styrene-co-maleic acid) (SMA) polymer to form "SMA Lipid Particles" (SMALPs) which have been widely adopted to solubilize membrane proteins directly from the cell membra

Influence of Poly(styrene-co-maleic acid) Copolymer Structure on the Properties and Self-Assembly of SMALP Nanodiscs

Polymer stabilized nanodiscs are self-assembled structures composed of a polymer belt that wraps around a segment of lipid bilayer, and as such are capable of encapsulating membrane proteins directly from the cell membrane. To date, most studies on these nanodiscs have used poly(styrene-co-maleic acid) (SMA) with the term SMA-lipid particles (SMALPs) coined to describe them. In this study, we have

Unravelling cationic cellulose nanofibril hydrogel structure : NMR spectroscopy and small angle neutron scattering analyses

Stiff, elastic, viscous shear thinning aqueous gels are formed upon dispersion of low weight percent concentrations of cationically modified cellulose nanofibrils (CCNF) in water. CCNF hydrogels produced from cellulose modified with glycidyltrimethylammonium chloride, with degree of substitution (DS) in the range 10.6(3)-23.0(9)%, were characterised using NMR spectroscopy, rheology and small angle

Decyltrimethylammonium Bromide Micelles in Acidic Solutions : Counterion Binding, Water Structuring, and Micelle Shape

Wide-angle neutron scattering experiments combined with empirical potential structural refinement modeling have been used to study the detailed structure of decyltrimethylammonium bromide micelles in the presence of acid solutions of HCl or HBr. These experiments demonstrate considerable variation in micelle structure and water structuring between micelles in the two acid solutions and in comparis

Thermal stability, storage and release of proteins with tailored fit in silica

Biological substances based on proteins, including vaccines, antibodies, and enzymes, typically degrade at room temperature over time due to denaturation, as proteins unfold with loss of secondary and tertiary structure. Their storage and distribution therefore relies on a “cold chain” of continuous refrigeration; this is costly and not always effective, as any break in the chain leads to rapid lo

Microwave-assisted deep eutectic-solvothermal preparation of iron oxide nanoparticles for photoelectrochemical solar water splitting

Here, we present a new microwave-solvothermal method for the preparation of iron oxide nanostructures using deep eutectic solvents as a more sustainable reaction medium. By varying the synthesis temperature and solvent water fraction, the methodology offers control over iron oxide phase, size, and morphology, using efficient, rapid (10 minute) microwave heating. Synthesis with pure DES gives small

The Effect of Water upon Deep Eutectic Solvent Nanostructure : An Unusual Transition from Ionic Mixture to Aqueous Solution

The nanostructure of a series of choline chloride/urea/water deep eutectic solvent mixtures was characterized across a wide hydration range by neutron total scattering and empirical potential structure refinement (EPSR). As the structure is significantly altered, even at low hydration levels, reporting the DES water content is important. However, the DES nanostructure is retained to a remarkably h

Sulfur-Doped Cubic Mesostructured Titania Films for Use as a Solar Photocatalyst

Sulfur-doped titania thin films with cubic mesostructures were prepared by dip coating via the evaporation induced self-assembly route. The effect of sulfur doping on structure, morphology, porosity, optical properties, and photocatalytic activity of the mesoporous films was studied. Compared to undoped titania films, the S-doped films showed better long-range ordering, bigger pore size, higher po

Coarse-grained empirical potential structure refinement : Application to a reverse aqueous micelle

Conventional atomistic computer simulations, involving perhaps up to 106 atoms, can achieve length-scales on the order of a few 10s of nm. Yet many heterogeneous systems, such as colloids, nano-structured materials, or biological systems, can involve correlations over distances up 100s of nm, perhaps even 1 μm in some instances. For such systems it is necessary to invoke coarse-graining, where sin