Deposition of silver nanoparticles into porous system of sol–gel silica monoliths and properties of silver/porous silica composites

This work reports a facile and inexpensive preparation of porous silica monolithsviaanin situsol–gel method using potassium silicate precursors in the presence of porosity controlling and drying regulatory additives.

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Development of Novel Oral Formulations of Disulfide Antioxidants Based on Porous Silica for Controlled Release of the Drugs

Materials ◽

10.3390/ma14040963 ◽

2021 ◽

Vol 14 (4) ◽

pp. 963

Author(s):

Ekaterina S. Dolinina ◽

Elena V. Parfenyuk

Keyword(s):

Antioxidant Activity ◽

Surface Chemistry ◽

Sol Gel ◽

Porous Silica ◽

The Body ◽

Oral Drug ◽

Therapeutic Concentration ◽

Release Process ◽

Zero Order Kinetics ◽

Long Time

Powerful antioxidant α-lipoic acid (LA) exhibits limited therapeutic efficiency due to its pharmacokinetic properties. Therefore, the purpose of this work was to evaluate the ability of silica-based composites of LA as well as its amide (lipoamide, LM), as new oral drug formulations, to control their release and maintain their therapeutic concentration and antioxidant activity in the body over a long time. The composites synthesized at different sol–gel synthesis pH and based on silica matrixes with various surface chemistry were investigated. The release behavior of the composites in media mimicking pH of digestive fluids (pH 1.6, 6.8, and 7.4) was revealed. The effects of chemical structure of the antioxidants, synthesis pH, surface chemistry of the silica matrixes in the composites as well as the pH of release medium on kinetic parameters of the drug release and mechanisms of the process were discussed. The comparative analysis of the obtained data allowed the determination of the most promising composites. Using these composites, modeling of the release process of the antioxidants in accordance with transit conditions of the drugs in stomach, proximal, and distal parts of small intestine and colon was carried out. The composites exhibited the release close to the zero order kinetics and maintained the therapeutic concentration of the drugs and antioxidant effect in all parts of the intestine for up to 24 h. The obtained results showed that encapsulation of LA and LM in the silica matrixes is a promising way to improve their bioavailability and antioxidant activity.

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Eco-fabrication of hierarchical porous silica monoliths by ice-templating of rice husk ash

Green Chemistry ◽

10.1039/c6gc02153k ◽

2017 ◽

Vol 19 (1) ◽

pp. 188-195 ◽

Cited By ~ 32

Author(s):

Amin Bahrami ◽

Ulla Simon ◽

Niloofar Soltani ◽

Sara Zavareh ◽

Johannes Schmidt ◽

...

Keyword(s):

Rice Husk ◽

Rice Husk Ash ◽

Porous Silica ◽

Synthesis Process ◽

Sustainable Chemistry ◽

Silica Monoliths ◽

Hierarchical Porous ◽

Ice Templating

In this study, within a sustainable chemistry approach, a clean and eco-friendly synthesis process of silica monoliths compatible with environmental limitations is developed.

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Bioencapsulation in Sol-Gel Glasses

MRS Proceedings ◽

10.1557/proc-519-171 ◽

1998 ◽

Vol 519 ◽

Cited By ~ 9

Author(s):

L. Bergogne ◽

S. Fennouh ◽

J. Livage ◽

C. Roux

Keyword(s):

Sol Gel ◽

Porous Silica ◽

Silica Matrix ◽

Whole Cells ◽

The Past ◽

Wide Range ◽

Activity Of Enzymes ◽

Gel Glasses ◽

Micro Organisms

AbstractBioencapsulation in sol-gel materials has been widely studied during the past decade. Trapped species appear to retain their bioactivity in the porous silica matrix. Small analytes can diffuse through the pores allowing bioreactions to be performed in-situ, inside the sol-gel glass. A wide range of biomolecules and micro-organisms have been encapsulated. The catalytic activity of enzymes is used for the realization of biosensors or bioreactors. Antibody-antigen recognition has been shown to be feasible within sol-gel matrices. Trapped antibodies bind specifically the corresponding haptens and can be used for the detection of traces of chemicals. Even whole cells are now encapsulated without any alteration of their cellular organization. They can be used for the production of chemicals or as antigens for immunoassays.

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Sol-Gel Derived Silica Layers for Low-k Dielectrics Applications

MRS Proceedings ◽

10.1557/proc-612-d5.26.1 ◽

2000 ◽

Vol 612 ◽

Cited By ~ 4

Author(s):

Sylvie Acosta ◽

André Ayral ◽

Christian Guizard ◽

Charles Lecornec ◽

Gérard Passemard ◽

...

Keyword(s):

Average Pore Size ◽

Sol Gel ◽

Porous Silica ◽

Thin Layers ◽

Gaseous Ammonia ◽

Potential Candidate ◽

Average Pore ◽

Synthesis Strategy ◽

Silica Layers ◽

Highly Porous

AbstractPorous silica exhibits attractive dielectric properties, which make it a potential candidate for use as insulator into interconnect structures. A new way of preparation of highly porous silica layers by the sol-gel route was investigated and is presented. The synthesis strategy was based on the use of common and low toxicity reagents and on the development of a simple process without gaseous ammonia post-treatment or supercritical drying step. Defect free layers were deposited by spin coating on 200 mm silicon wafers and characterized. Thin layers with a total porosity larger than 70% and an average pore size of 5 nm were produced. The dielectric constant measured under nitrogen flow on these highly porous layers is equal to ∼ 2.5, which can be compared to the value calculated from the measured porosity, ∼ 1.9. This difference is explained by the presence of water adsorbed on the hydrophilic surface of the unmodified silica.

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In Situ ATR-FT-IR Kinetic Studies of Molecular Transport and Surface Binding in Thin Sol−Gel Films: Reactions of Chlorosilane Reagents in Porous Silica Materials

Analytical Chemistry ◽

10.1021/ac000947j ◽

2001 ◽

Vol 73 (3) ◽

pp. 411-423 ◽

Cited By ~ 28

Author(s):

Dion Rivera ◽

Joel M. Harris

Keyword(s):

Sol Gel ◽

Porous Silica ◽

Molecular Transport ◽

Kinetic Studies ◽

Surface Binding ◽

Silica Materials ◽

Ft Ir ◽

Sol Gel Films

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Humidity Effects on Porous Silica Thin Films

MRS Proceedings ◽

10.1557/proc-411-419 ◽

1995 ◽

Vol 411 ◽

Cited By ~ 2

Author(s):

J. R. Kokan ◽

R. A. Gerhardt

Keyword(s):

Thin Films ◽

Ac Conductivity ◽

Sol Gel ◽

Porous Silica ◽

Controlled Environment ◽

Alkali Ions ◽

Humidity Effects ◽

Silica Thin Films ◽

Environment Chamber ◽

Humidity Sensitivity

ABSTRACTImpedance Spectroscopy is being used to study the humidity sensitivity of porous silica thin films. The films are processed via a colloidal sol-gel method which leaves some remnant potassium and sodium. Previous work on bulk porous silica samples processed by the same method showed that the dielectric properties and ac conductivity were very sensitive to changes in humidity. The aim of this work was to determine if the same dependencies could be found in the thin films. The capacitance, dielectric loss, and ac conductivity of the films were measured in a controlled environment chamber from 20–80% RH for frequencies ranging from 10Hz–10MHz. In addition to characterizing films with varying amounts of residual alkali ions obtained through leaching, we have also measured films that were surface doped with controlled amounts of KCl, LiCl, or NaCl. Relative humidity dependencies in the films are not as dramatic as in the bulk samples. The reasons for this behavior are not yet clear, but may be associated with the porosity, thickness, and surface area of the films.

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