The preparation of TiO2/SiO2 composite hollow spheres with hydrophobic inner surface and their application in controlled release

Dps proteins are the structural relatives of bacterioferritins and ferritins ubiquitously present in the bacterial and archaeal kingdoms. The ball-shaped enzymes play important roles in the detoxification of ROS (reactive oxygen species), in iron scavenging to prevent Fenton reactions and in the mechanical protection of DNA. Detoxification of ROS and iron chaperoning represent the most archetypical functions of dodecameric Dps enzymes. Recent crystallographic studies of these dodecameric complexes have unravelled species-dependent mechanisms of iron uptake into the hollow spheres. Subsequent functions in iron oxidation at ferroxidase centres are highly conserved among bacteria. Final nucleation of iron as iron oxide nanoparticles has been demonstrated to originate at acidic residues located on the inner surface. Some Dps enzymes are also implicated in newly observed catalytic functions related to the formation of molecules playing roles in bacterium–host cell communication. Most recently, Dps complexes are attracting attention in semiconductor science as biomimetic tools for the technical production of the smallest metal-based quantum nanodots used in nanotechnological approaches, such as memory storage or solar cell development.

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Selective Modification and Application for Controlled Release of TiO2/SiO2 Composite Hollow Spheres

Journal of Inorganic Materials ◽

10.3724/sp.j.1077.2010.00201 ◽

2010 ◽

Vol 25 (2) ◽

pp. 201-205

Author(s):

Li-Feng YAO ◽

Yan SHI ◽

Li-Li WEN ◽

Qiang SHEN ◽

Lian-Meng ZHANG

Keyword(s):

Controlled Release ◽

Hollow Spheres

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Copper on the inner surface of mesoporous TiO2 hollow spheres: a highly selective photocatalyst for partial oxidation of methanol to methyl formate

Catalysis Science & Technology ◽

10.1039/c9cy01595g ◽

2019 ◽

Vol 9 (22) ◽

pp. 6240-6252 ◽

Cited By ~ 5

Author(s):

Changfu Li ◽

Xuzhuang Yang ◽

Guanjun Gao ◽

Yuanyuan Li ◽

Weida Zhang ◽

...

Keyword(s):

Partial Oxidation ◽

Methyl Formate ◽

Hollow Spheres ◽

Methanol Conversion ◽

Mesoporous Tio2 ◽

Oxidation Of Methanol ◽

Partial Oxidation Of Methanol ◽

Inner Surface ◽

Tio2 Hollow Spheres

To raise the methyl formate (MF) selectivity at high methanol conversion is one of the most challenging topics for photocatalytic partial oxidation of methanol to MF.

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ВПЛИВ РОЗМІРУ ПОР ТА МОРФОЛОГІЇ МЕЗОПОРИСТОГО КРЕМНІЮ НА ВИВІЛЬНЕННЯ МЕТОПРОЛОЛУ ТАРТРАТУ

Technologies and Engineering ◽

10.30857/2786-5371.2021.5.2 ◽

2022 ◽

pp. 18-25

Author(s):

HONGJUAN WANG ◽

WEI HU ◽

OLENA SALIY

Keyword(s):

Controlled Release ◽

Drug Release ◽

Mesoporous Silica ◽

Silicon Dioxide ◽

Functional Groups ◽

Chemical Engineering ◽

Hollow Spheres ◽

Metoprolol Tartrate ◽

Mesoporous Silicon ◽

Mesoporous Silicon Dioxide

Purpose. Study pore size effect and morphology of mesoporous silica on metoprolol tartrate release.Methodology. A sample of hollow mesoporous silicon dioxide with amino-functional groups containing 12.7 wt. % metoprolol tartrate has been investigated as potential carriers for the controlled release of active substance. Studies of the release profiles of metoprolol tartrate were performed under the following conditions: dissolution medium was buffer solution with a pH of 7.4 (phosphate buffer); sampling time: from 0.5 h before 18 h. The metoprolol concentration in the liquid phase was evaluated by a UV-Vis spectrophotometer (Persee TU-190, Beijing, China) by use of quartz cuvettes with an optical path length of 1 cm at a maximum wavelength of 274 nm.Findings. In this work we have studied mesoporous silica as possible carrier to controlled release of metoprolol tartrate, a drug used in the treatment of some diseases of the cardiovascular system. The material for research was a sample of hollow mesoporous silicon dioxide with amino-functional groups 200–400 nm in size and 20–30 nm in shell thickness. A calibrated curve to determine the amount of metoprolol was constructed by determining the absorption dependence of the concentration of metoprolol in the range from 10 to 300 ppm. The same drug concentration was obtained as calculated from the drug release test formula, which concludes that the release of metoprolol is controlled.Originality. The controlled release of a sample of hollow spheres of mesoporous silicon dioxide filled with metoprolol tartrate was studied, which was synthesized by the School of Chemistry and Chemical Engineering, Qilu University of Technology, using a new technology, where hollow spheres of mesoporous silicon dioxide with amino groups were synthesized using CO2 gas bubbles as templates.Practical value. The metoprolol release amount could achieve a 50% release amounts within 1 hour and 90% within 5 hours, indicating that the synthesized mesoporous hollow sphere could achieve controlled drug release, and shows the potential of carriers with stimulus response and targeted therapy.

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An analytical solution for the stress distribution within a spherically isotropic hollow sphere under diametrical compression

Mathematics and Mechanics of Solids ◽

10.1177/1081286518783217 ◽

2018 ◽

Vol 24 (5) ◽

pp. 1256-1278 ◽

Cited By ~ 1

Author(s):

Lintong Yan ◽

Xuexia Wei

Keyword(s):

Analytical Solution ◽

Shear Modulus ◽

Tensile Stress ◽

Hollow Sphere ◽

Hollow Spheres ◽

Maximum Tensile Stress ◽

Stress Distributions ◽

Stress Concentrations ◽

Inner Surface ◽

Symmetric Deformation

An analytical solution for the stress distributions within a spherically isotropic hollow sphere under diametrical compression is derived. The deformation of the spherically isotropic hollow sphere is divided into axis-symmetric deformation and non-symmetric deformation. The analytical solution for the axis-symmetric deformation is obtained by following the displacement method, while that for non-symmetric deformation of the spherically isotropic hollow sphere is obtained by employing the displacement function method. When the isotropic limit is considered, the analytical solution for isotropic hollow spheres is recovered identically. Numerical results show that tensile stress concentrations are usually developed both at the inner surface and near r/ R = 0.85 within a hollow sphere along the axis of loading. A small value of the anisotropy in Young’s modulus or Poisson’s ratio usually leads to a large value of the maximum tensile stress at the inner surface. While a smaller value of the anisotropy in Poisson’s ratio or a large value of the anisotropy in the shear modulus may lead to a large value of the maximum tensile stress near r/ R = 0.85 for a thick and anisotropic hollow sphere. In addition, it is found that the anisotropy in the shear modulus has drastic influence on the tensile stress distributions within a thin hollow sphere, and a particular value of the anisotropy in the shear modulus may reduce greatly the tensile stress concentrations both at inner surface and near r/ R = 0.85 of a thin hollow sphere. This result may provide us a very attractive method to optimize the elastic constants of anisotropic hollow spheres by synthesis process technique so as to improve the load capacity of a hollow sphere, and extend the fatigue life of composite material made of thin hollow spheres.

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Synthesis of mesoscopic hollow spheres and inner surface functionalized hollow spheres of titanium dioxide by the liquid phase deposition method

Journal of Materials Research ◽

10.1557/jmr.2003.0395 ◽

2003 ◽

Vol 18 (12) ◽

pp. 2832-2836 ◽

Cited By ~ 16

Author(s):

Yoshifumi Aoi ◽

Hisae Kambayashi ◽

Eiji Kamijo ◽

Shigehito Deki

Keyword(s):

Titanium Dioxide ◽

Reaction Time ◽

Liquid Phase ◽

Hollow Spheres ◽

Composite Particles ◽

Liquid Phase Deposition ◽

Deposition Method ◽

Inner Surface ◽

Shell Composite

Polystyrene (PS) core–TiO2 shell composite particles and TiO2 hollow spheres were fabricated using the liquid phase deposition (LPD) method. Composite particles were prepared using PS particles as templates. Calcination of the composite particles resulted in TiO2 hollow spheres. Uniform TiO2 hollow spheres were obtained when the reaction time of the LPD process was between 4 and 8 h. Furthermore, we fabricated TiO2 hollow spheres whose inner surfaces were functionalized by Pt particles after platinized PS particles were used as templates. The Pt particles were immobilized on the inner surfaces of the hollow spheres.

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Synthesis of Breathing Metallopolymer Hollow Spheres for Redox-Controlled Release

Macromolecular Rapid Communications ◽

10.1002/marc.201600338 ◽

2016 ◽

Vol 37 (19) ◽

pp. 1573-1580 ◽

Cited By ~ 22

Author(s):

Daniel Scheid ◽

Moritz von der Lühe ◽

Markus Gallei

Keyword(s):

Controlled Release ◽

Hollow Spheres

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A SEM and Light Microscope Study of the Epidermal Leaf Structures of the Carnivorous Plant, Sarracenia purpurea, L.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100065833 ◽

1971 ◽

Vol 29 ◽

pp. 358-359

Author(s):

B. J. Panessa ◽

J. F. Gennaro

Keyword(s):

Methylene Blue ◽

Toluidine Blue ◽

Outer Surface ◽

Microscope Study ◽

Light Microscope ◽

Carnivorous Plant ◽

Sarracenia Purpurea ◽

Inner Surface

Tissue from the hood and sarcophagus regions were fixed in 6% glutaraldehyde in 1 M.cacodylate buffer and washed in buffer. Tissue for SEM was partially dried, attached to aluminium targets with silver conducting paint, carbon-gold coated(100-500Å), and examined in a Kent Cambridge Stereoscan S4. Tissue for the light microscope was post fixed in 1% aqueous OsO4, dehydrated in acetone (4°C), embedded in Epon 812 and sectioned at ½u on a Sorvall MT 2 ultramicrotome. Cross and longitudinal sections were cut and stained with PAS, 0.5% toluidine blue and 1% azure II-methylene blue. Measurements were made from both SEM and Light micrographs.The tissue had two structurally distinct surfaces, an outer surface with small (225-500 µ) pubescent hairs (12/mm2), numerous stoma (77/mm2), and nectar glands(8/mm2); and an inner surface with large (784-1000 µ)stiff hairs(4/mm2), fewer stoma (46/mm2) and larger, more complex glands(16/mm2), presumably of a digestive nature.

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Gastric Ulcers Produced by Cisplatin

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100099337 ◽

1981 ◽

Vol 39 ◽

pp. 582-583

Author(s):

S.K. Aggarwal ◽

J. San Antonio

Keyword(s):

Electron Microscopy ◽

Single Dose ◽

Side Effects ◽

Antitumor Agent ◽

Gastric Ulcers ◽

Enzyme Cytochemistry ◽

Intestinal Toxicity ◽

Ovarian Cancers ◽

Inner Surface

Cisplatin (cis-dichlorodiammineplatinum(II)) a potent antitumor agent is now available for the treatment of testicular and ovarian cancers. It is however, not free from its serious side effects including nephrotoxicity, gastro intestinal toxicity, myelosuppression, and ototoxicity. Here we now report that the drug produces peculiar bloating of the stomach in rats and induces acute ulceration.Wistar-derived rats weighing 200-250 g were administered cisplatin(9 mg/kg) ip as a single dose in 0.15 M NaCl. After 3 days the animals were sacrificed by decapitation. The stomachs were removed, the contents analyzed for pepsin and acidity. The inner surface was examined with a dissecting microscope after a moderate stretching for ulcers. Affected areas were fixed and processed for routine electron microscopy and enzyme cytochemistry.The drug treated animals kept on food and water consistently showed bloating and lesions (Fig. 1) with a frequency of 6-70 ulcers in the rumen section of the stomachs.

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