Nutrients in Bamboo Shoots
Nirmala Chongtham, Madho Singh Bisht in Bamboo Shoot, 2020
Silicon (Si) is a non-metallic element and the second most abundant element in the Earth’s crust with a great affinity for oxygen, forming 92% silica and silicates. It is also the most abundantly available trace element after iron and zinc. Chemically, silica is an oxide of silicon, viz. silicon dioxide and is generally colourless to white and insoluble in water. When associated with metals or minerals the family of silicates is formed. Humans are exposed to numerous sources of silica/silicon including dust, food, pharmaceuticals, cosmetics and medical implants and devices. As a metalloid, silicon has been used in many industrial applications including use as an additive in the food and beverage industry. As a result, humans are exposed to silicon through both environmental exposures and also as a dietary component. Bamboo extract is the richest known source of natural silica, containing over 70% organic silica. This is more than 10 times the level found in the widely used Horsetail plant (Equisetum) that contains 5% to 7% silica.
Advanced Biotechnology
Lawrence S. Chan, William C. Tang in Engineering-Medicine, 2019
Silicon oxide is the sacrificial material of choice for polysilicon or SOI surface micromachining. It can be grown or deposited by a number of means. Exposure of silicon surfaces at high temperatures (1000°C and higher) in oxygen grows high-quality silicon dioxide films. This thermal oxidation process is common in the IC industry, and thus is well characterized and highly reproducible. However, the oxide film expands in volume by about 45% while consuming the adjacent silicon material, thus it creates a compressive stress in the silicon parts. Alternatively, oxide films can be deposited by LPCVD using the pyrolytic reaction of silane and oxygen at a pressure of 300–500 mT and a temperature of 450°C. Because of the substantially lower temperature of deposition compared to oxidation, LPCVD oxides are commonly called low-temperature oxides (LTO).
Organo-Modified Siloxane Polymers for Conditioning Skin and Hair
Randy Schueller, Perry Romanowski in Conditioning Agents for Hair and Skin, 2020
The basic raw material from which silicones are formed is quartz, i.e., silica or silicon dioxide (SiCh). In the form of crystals or fine grains, quartz is the main constituent of white sand. In 1824, Jons-Jacob Berzelius, a Swedish chemist, was successful in liberating elemental silicon (Si) from quartz by reduction of potassium fluorosilicate with potassium. Alkylation of elemental silicon to prepare alkyl silanes was done initially by Friedel and Crafts (1863) using zinc compounds, by Kipping (1904) using organo-magnesium compounds (Grignard reaction), and independently in the 1930s by Hyde (Corning Glass Works) and Rochow (General Electric) using methyl chloride. These scientists synthesized the silicon-carbon bond—one of the most important steps in the history of organo-siloxane polymer development (1,2). The silicon-oxygen-silicon backbone was synthesized by Ladenburg in 1871 by hydrolyzing diethyldiethoxysilane in the presence of a dilute acid to form an oil (silicone). Between 1899 and 1944, Kipping published 54 papers on the subject of silicon chemistry, describing the first systematic study in the field. This work helped Hyde and Rochow develop a commercial process—"the direct process"— using elemental silicon and methyl chloride to produce organo-silicon compounds. Current reviews of the synthesis of organo-siloxane polymers have been written by Colas (3) and Rhone Poulenc (4).
Small interfering RNA-based nanotherapeutics for treating skin-related diseases
Published in Expert Opinion on Drug Delivery, 2023
Yen-Tzu Chang, Tse-Hung Huang, Ahmed Alalaiwe, Erica Hwang, Jia-You Fang
MSNs feature a porous network within the silicon oxide matrix. They have a broad range of applications, such as adsorbents, energy storage, sensors, and drug delivery vehicles [47]. It is practical to load the chemicals inside the mesopores with high loading efficiency, controlled delivery, and increased drug stability. The attractive characteristics of MSNs are the flexibility of surface functionalization and pore size control for improving drug incorporation and targeting [48]. A powerful tool of MSNs is their ability to carry siRNA molecules for passage through the cell membrane and release the cargo at their destination [49]. The native silicon oxide surface is anionic, repelling the interaction with nucleic acids. Surface functionalization with cationic materials is often needed to effectively load RNA-based agents [50]. The porous structure of MSNs enables the entrapment of two or more therapeutics to exhibit synergistic bioactivity [51]. MSN-based skin delivery has sparked some interest due to the high drug loading, enhancement in drug stability, absorption, and ease of functionalization. The functionalization of MSNs manifests a key capacity to facilitate the skin delivery of therapeutic agents in a highly sustained fashion [52].
Silicon dioxide nanoparticle exposure affects small intestine function in an in vitro model
Published in Nanotoxicology, 2018
Zhongyuan Guo, Nicole J. Martucci, Yizhong Liu, Eusoo Yoo, Elad Tako, Gretchen J. Mahler
Food-grade silicon dioxide (SiO2) or amorphous silica (coded E551) has been found to contain particles in the nano-size range (at least one dimension less than 100 nanometers) (Auffan et al. 2009; Dekkers et al. 2011; Peters et al. 2012; Yang et al. 2016). Similar to TiO2 NP, SiO2 nanoparticles (NP) are used to improve the taste and texture of rich foods without adding calories, preserve food color and durability, and carry fragrances or flavors (Dekkers et al. 2011; Contado et al. 2016). SiO2 NP also act as anti-caking agents to maintain flow properties of powdered mixes, seasonings, and coffee whiteners (Dekkers et al. 2011; Contado et al. 2016). The use of nanomaterials in food production and pharmaceutics, however, may have unknown health effects due to unexpected biological interactions (Dekkers et al. 2011).
Facile deposition of biogenic silver nanoparticles on porous alumina discs, an efficient antimicrobial, antibiofilm, and antifouling strategy for functional contact surfaces
Published in Biofouling, 2021
Ozioma Forstinus Nwabor, Sudarshan Singh, Suttiwan Wunnoo, Kowit Lerwittayanon, Supayang Piyawan Voravuthikunchai
The XRD pattern of AD-AgNPs, AD-AgNO3, AD-PE, and AD-control are presented in Figure 3. The peaks observed at 38.17°, 44.37°, and 64.58° correspond to (111), (200), (222) and (220) reflection planes of a face-centred cubic structure (fcc) of silver (ICDD database), respectively (Li J et al. 2020). Furthermore, the peaks observed at 25.57°, 35.16°, 38.21°, 44.43°, 52.54°, 57.45°, 61.27°, 64.45°, 68.10°, 77.17°, 80.76°, 84.32°, 86.40°, and 88.96° correspond to (012), (104), (110), (113), (024), (116), (112), (214), (300), (119), (220), (223), and (0210) reflection planes of a fcc aluminium oxide (ICDD database), respectively. The inter-planar spacing (dcal) values of AD-AgNPs were 2.35, 2.03, 1.60, and 1.44 Å compared with standard silver, and 3.48, 2.55, 2.35, 2.03, 1.74, 1.60, 1.51, 1.44, 1.37, 1.23, 1.18, 1.14, 1.12, and 1.10 Å for Al2O3 compared with standard aluminium oxide. Additionally, the peaks around 25.56°, 35.16°, 37.84°, and 43.30° are due to the presence of silicon oxide (Il’ves et al. 2015). The diffraction peaks at 25.56° and 80.64° correspond to (012 and 220) plan which indexed to fcc for α-Al2O3 and γ-Al2O3, respectively, a metastable phase of alumina (Papi et al. 2015; Ismail et al. 2017). The silver peaks in the XRD pattern significantly support the formation of nano-sized particles over the alumina discs (Valsalam et al. 2019). The average crystallite size of silver nanoparticles was calculated to be between 64.56 nm and 78.08 nm.
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