scholarly journals Using crystallography tools to improve vaccine formulations

IUCrJ ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Márcia Carvalho de Abreu Fantini ◽  
Cristiano Luis Pinto Oliveira ◽  
José Luiz de Souza Lopes ◽  
Tereza da Silva Martins ◽  
Milena Apetito Akamatsu ◽  
...  
Keyword(s):  
Oral Vaccine ◽  
Porous Silica ◽  
Protein Antigens ◽  
X Ray ◽  
X Ray Crystallography ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
X Ray Imaging ◽  
The Stability ◽  
Phase Contrast Tomography

This article summarizes developments attained in oral vaccine formulations based on the encapsulation of antigen proteins inside porous silica matrices. These vaccine vehicles show great efficacy in protecting the proteins from the harsh acidic stomach medium, allowing the Peyer's patches in the small intestine to be reached and consequently enhancing immunity. Focusing on the pioneering research conducted at the Butantan Institute in Brazil, the optimization of the antigen encapsulation yield is reported, as well as their distribution inside the meso- and macroporous network of the porous silica. As the development of vaccines requires proper inclusion of antigens in the antibody cells, X-ray crystallography is one of the most commonly used techniques to unveil the structure of antibody-combining sites with protein antigens. Thus structural characterization and modelling of pure antigen structures, showing different dimensions, as well as their complexes, such as silica with encapsulated hepatitis B virus-like particles and diphtheria anatoxin, were performed using small-angle X-ray scattering, X-ray absorption spectroscopy, X-ray phase contrast tomography, and neutron and X-ray imaging. By combining crystallography with dynamic light scattering and transmission electron microscopy, a clearer picture of the proposed vaccine complexes is shown. Additionally, the stability of the immunogenic complex at different pH values and temperatures was checked and the efficacy of the proposed oral immunogenic complex was demonstrated. The latter was obtained by comparing the antibodies in mice with variable high and low antibody responses.

scholarly journals On the Stability of 3C-SiC Single Crystals at High Temperatures

2012 ◽  
Vol 717-720 ◽  
pp. 493-496
Author(s):  
Deborah Dompoint ◽  
Irina G. Galben-Sandulache ◽  
Alexandre Boulle ◽  
Didier Chaussende ◽  
Dominique Eyidi ◽  
...  
Keyword(s):  
Single Crystals ◽  
Volume Fraction ◽  
Diffuse Intensity ◽  
X Ray ◽  
Partial Dislocations ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
The Stability ◽  
Kinetics Of ◽  
Evolution With Time

The 3C-6H polytypic transition in 3C-SiC single crystals is studied by means of diffuse X-ray scattering (DXS) coupled with transmission electron microscopy (TEM). TEM reveals that the partially transformed SiC crystals contain regions of significantly transformed SiC (characterized by a high density of stacking faults) co-existing with regions of pure 3C-SiC. The simulation of the diffuse intensity allows to determine both the volume fraction of transformed material and the transformation level within these regions. It is further shown that the evolution with time and temperature of the transition implies the multiplication and glide of partial dislocations, the kinetics of which are quantified by means of DXS.

FDU-12 Mesoporous Materials Detection Hg (II) Ions by QCM

NANO ◽  
2016 ◽  
Vol 11 (08) ◽  
pp. 1650094 ◽  
Author(s):  
Huihui Lou ◽  
Chong Shen ◽  
Qun Xiang ◽  
Jiaqiang Xu ◽  
Tianjun Lou
Keyword(s):  
Electron Microscopy ◽  
Mesoporous Silica ◽  
Three Dimensional ◽  
Pore Channel ◽  
X Ray ◽  
X Ray Scattering ◽  
Sensing Material ◽  
Transmission Electron ◽  
The Stability ◽  
Better Than

Thiol-functionalized three-dimensional (3D) mesoporous silica FDU-12 and SBA-15 with ordered pore were prepared. All the obtained materials were characterized by small angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Mesoporous silica FDU-12 (Fm3m) materials with various unit cell sizes, multifaceted pore were convenient for the interaction of subject and object; the 2D SBA-15 mesoporous silica materials with short and order pore channel were better than the traditional SBA-15 mesoporous silica, in which the pore channel can be used fully. 3D mesoporous silica FDU-12 is used as a sensing material to reconstruct QCM sensors to enhance the stability and this material is an ideal material to deal with heavy metal ions in water.

scholarly journals Alpha helical surfactant-like peptides self-assemble into pH-dependent nanostructures

Soft Matter ◽  
2021 ◽  
Vol 17 (11) ◽  
pp. 3096-3104
Author(s):  
Valeria Castelletto ◽  
Jani Seitsonen ◽  
Janne Ruokolainen ◽  
Ian W. Hamley
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Small Angle ◽  
Self Assembly ◽  
X Ray ◽  
Cryogenic Transmission Electron Microscopy ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Ph Dependent ◽  
Ray Scattering

A designed surfactant-like peptide is shown, using a combination of cryogenic-transmission electron microscopy and small-angle X-ray scattering, to have remarkable pH-dependent self-assembly properties.

scholarly journals Facile Organometallic Synthesis of Fe-Based Nanomaterials by Hot Injection Reaction

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1141
Author(s):  
Georgia Basina ◽  
Hafsa Khurshid ◽  
Nikolaos Tzitzios ◽  
George Hadjipanayis ◽  
Vasileios Tzitzios
Keyword(s):  
Room Temperature ◽  
Colloidal Particles ◽  
Iron Pentacarbonyl ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
Organometallic Synthesis ◽  
X Ray ◽  
Transmission Electron ◽  
Hot Injection ◽  
The Stability

Fe-based colloids with a core/shell structure consisting of metallic iron and iron oxide were synthesized by a facile hot injection reaction of iron pentacarbonyl in a multi-surfactant mixture. The size of the colloidal particles was affected by the reaction temperature and the results demonstrated that their stability against complete oxidation related to their size. The crystal structure and the morphology were identified by powder X-ray diffraction and transmission electron microscopy, while the magnetic properties were studied at room temperature with a vibrating sample magnetometer. The injection temperature plays a very crucial role and higher temperatures enhance the stability and the resistance against oxidation. For the case of injection at 315 °C, the nanoparticles had around a 10 nm mean diameter and revealed 132 emu/g. Remarkably, a stable dispersion was created due to the colloids’ surface functionalization in a nonpolar solvent.

Comparative Studies of Ultra Low-κ Porous Silica Films with 2-D Hexagonal and Disordered Pore Structures

2004 ◽  
Vol 812 ◽  
Author(s):  
Nobutoshi Fujii ◽  
Kazuhiro Yamada ◽  
Yoshiaki Oku ◽  
Nobuhiro Hata ◽  
Yutaka Seino ◽  
...  
Keyword(s):  
Pore Structure ◽  
Nonionic Surfactants ◽  
Porous Silica ◽  
Silica Film ◽  
X Ray Diffraction ◽  
Silica Films ◽  
X Ray ◽  
X Ray Scattering ◽  
Porous Silica Film ◽  
Diffraction Peaks

AbstractPeriodic 2-dimensional (2-D) hexagonal and the disordered pore structure silica films have been developed using nonionic surfactants as the templates. The pore structure was controlled by the static electrical interaction between the micelle of the surfactant and the silica oligomer. No X-ray diffraction peaks were observed for the disordered mesoporous silica films, while the pore diameters of 2.0-4.0 nm could be measured by small angle X-ray scattering spectroscopy. By comparing the properties of the 2-D hexagonal and the disordered porous silica films which have the same porosity, it is found that the disordered porous silica film has advantages in terms of the dielectric constant and Young's modulus as well as the hardness. The disordered porous silica film is more suitable for the interlayer dielectrics for ULSI.

On the selective aerobic oxidation of benzyl alcohol with Pd/Au-nanoparticles in batch and flow

2014 ◽  
Vol 3 (1) ◽  
pp. 99-110 ◽  
Author(s):  
Hannes Alex ◽  
Norbert Steinfeldt ◽  
Klaus Jähnisch ◽  
Matthias Bauer ◽  
Sandra Hübner
Keyword(s):  
Catalytic Activity ◽  
Benzyl Alcohol ◽  
Aerobic Oxidation ◽  
X Ray ◽  
X Ray Scattering ◽  
Oxidation Of Benzyl Alcohol ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Selective Aerobic Oxidation

AbstractNanoparticles (NP) have specific catalytic properties, which are influenced by parameters like their size, shape, or composition. Bimetallic NPs, composed of two metal elements can show an improved catalytic activity compared to the monometallic NPs. We, herein, report on the selective aerobic oxidation of benzyl alcohol catalyzed by unsupported Pd/Au and Pd NPs at atmospheric pressure. NPs of varying compositions were synthesized and characterized by UV/Vis spectroscopy, transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS). The NPs were tested in the model reaction regarding their catalytic activity, stability, and recyclability in batch and continuous procedure. Additionally, in situ extended X-ray absorption fine structure (EXAFS) measurements were performed in order to get insight in the process during NP catalysis.

An X-ray scattering study on inverted Ge–Si huts grown at low temperatures

2004 ◽  
Vol 19 (4) ◽  
pp. 347-351
Author(s):  
J. Xu ◽  
X. S. Wu ◽  
B. Qian ◽  
J. F. Feng ◽  
S. S. Jiang ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Lattice Strain ◽  
Lattice Mismatch ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Large Lattice ◽  
Scattering Study

Ge–Si inverted huts, which formed at the Si∕Ge interface of Si∕Ge superlattice grown at low temperatures, have been measured by X-ray diffraction, grazing incidence X-ray specular and off-specular reflectivities, and transmission electron microscopy (TEM). The surface of the Si∕Ge superlattice is smooth, and there are no Ge–Si huts appearing on the surface. The roughness of the surfaces is less than 3 Å. Large lattice strain induced by lattice mismatch between Si and Ge is found to be relaxed because of the intermixing of Ge and Si at the Si∕Ge interface.

Analysis of InGaN/GaN single quantum wells by X-ray scattering and transmission electron microscopy

2003 ◽  
Vol 240 (2) ◽  
pp. 297-300 ◽  
Author(s):  
T. M. Smeeton ◽  
M. J. Kappers ◽  
J. S. Barnard ◽  
M. E. Vickers ◽  
C. J. Humphreys
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Quantum Wells ◽  
Single Quantum ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Ray Scattering

X-ray imaging with ultra-small-angle X-ray scattering as a contrast mechanism

2004 ◽  
Vol 37 (5) ◽  
pp. 757-765 ◽  
Author(s):  
L. E. Levine ◽  
G. G. Long
Keyword(s):  
Small Angle ◽  
Imaging Technique ◽  
Three Dimensional ◽  
Sample Volume ◽  
Contrast Imaging ◽  
X Ray ◽  
X Ray Scattering ◽  
X Ray Imaging ◽  
Contrast Mechanism ◽  
Ray Scattering

A new transmission X-ray imaging technique using ultra-small-angle X-ray scattering (USAXS) as a contrast mechanism is described. USAXS imaging can sometimes provide contrast in cases where radiography and phase-contrast imaging are unsuccessful. Images produced at different scattering vectors highlight different microstructural features within the same sample volume. When used in conjunction with USAXS scans, USAXS imaging provides substantial quantitative and qualitative three-dimensional information on the sizes, shapes and spatial arrangements of the scattering objects. The imaging technique is demonstrated on metal and biological samples.

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