Synthesis of SiO<sub>2</sub> nanopowders containing quartz and cristobalite phases from silica sands

Munasir, Munasir; Triwikantoro, T.; Zainuri, Mochamad; Darminto, Darminto

doi:10.1515/msp-2015-0008

Cited by 79 publications

(36 citation statements)

References 22 publications

(34 reference statements)

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“…Silica is an enormously abundant indigenous material; e.g. it is the main component from beach sand and can be extracted easily [28,29] (Fig. S1) and used directly without size selection (see Fig.…”

Section: Silica Integrationmentioning

confidence: 99%

Gene to diagnostic: Self immobilizing protein for silica microparticle biosensor, modelled with sarcosine oxidase

et al. 2019

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A rational design approach is proposed for a multifunctional enzyme reagent for point-of-care diagnostics. The biomaterial reduces downstream isolation steps and eliminates immobilization coupling chemicals for integration in a diagnostic platform. Fusion constructs combined the central functional assay protein (e.g. monomeric sarcosine oxidase, mSOx, horseradish peroxidase, HRP), a visualizing protein (e.g. mCherry) and an in-built immobilization peptide (e.g. R5). Monitoring protein expression in E.coli was facilitated by following the increase in mCherry fluorescence, which could be matched to a color card, indicating when good protein expression has occurred. The R5 peptide (SSKKSGSYSGSKGSKRRIL) provided inbuilt affinity for silica and an immobilization capability for a silica based diagnostic, without requiring additional chemical coupling reagents. Silica particles extracted from beach sand were used to collect protein from crude protein extract with 85-95% selective uptake. The silica immobilized R5 proteins were stable for more than 2 months at room temperature. The Km for the silica-R52-mCh-mSOx-R5-6H was 16.5±0.9mM (compared with 16.5±0.4 mM, 16.3±0.3 mM, and 16.1±0.4 mM for R52-mCh-mSOx-R5-6H, mSOx-R5-6H and mSOx-6H respectively in solution). The use of the "silica-enzymes" in sarcosine and peroxide assays was shown, and a design using particle sedimentation through the sample was examined. Using shadowgraphy and particle image velocimetry the particle trajectory through the sample was mapped and an hourglass design with a narrow waist shown to give good control of particle position. The hourglass biosensor was demonstrated for sarcosine assay in the clinically useful range of 2.5 to 10 µM in both a dynamic and end point measurement regime.

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Section: Silica Integrationmentioning

confidence: 99%

Gene to diagnostic: Self immobilizing protein for silica microparticle biosensor, modelled with sarcosine oxidase

et al. 2019

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“…Bands between 1 200 -1 180 cm -1 was assigned to the longitudinal optical (LO) modes of the Si-O-Si asymmetric stretching vibrations, bands at the interval of 1 128 -1 060 cm -1 was assigned to the transversal optical (TO) modes of the Si-O-Si asymmetric stretching vibrations, while a weak band around 657 cm -1 was assigned to Si-O stretching of the SiO 2 and finally the 468 cm -1 band was associated with Si-O symmetrical bending vibration. The detected vibrations reveal the presence of quartz [24]. Figure 2b shows the XRD patterns of the sands which are in total accordance with reflections corresponding to quartz SiO 2 ((JCPDS # 01-083-2465).…”

Section: Characterization Of Raw Materialsmentioning

confidence: 53%

Exploring the use of silica sands and calcite from natural deposits to prepare bioactive glasses

Alonso

García-Menocal

Garcı́a-Vallés

et al. 2018

International Journal of Materials Research

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Nowadays bioactive glasses represent one of the most successful bioceramics used for bone tissue restorations. In this work, three types of silica sands (White, Yellow and Gray sands) and calcite from Cuban natural deposits were employed to synthesize glasses from the system SiO 2-CaO-Na 2 O. The ions released from glasses were evaluated through in vitro tests in Tris-HCl and in simulated body fluids. All sands had purity around 99.2 % of SiO 2 and contained traces (ppm) of Zr, Cr, Ba, Ce and Sr ions, while calcite raw material had traces of Sr, Cr, Zr, Ce and Zn. All glasses induced a pH change in Tris-HCl from 7.4 to 9 after 24 h; they had similar ion-release behavior in the in vitro solutions tested and showed a significant bioactive performance after 5 h. This work illustrates the potentialities of the use of natural resources to develop medical products when recognized trademark materials are not available.

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“…The FT-IR spectrum of the silica reveals the silanol groups between 950-964 cm −1 , which are the characteristic FT-IR bands of the αquartz. The predominant absorbance bands at 1077 cm −1 were assigned to Si-O-Si asymmetric stretching vibrations [24,25]. On the other hand, the FT-IR spectrum of the β-carotene exhibits a narrow band at 1400 cm −1 associated with C-H stretching vibration mode, the bands observed between 1000-1200 cm −1 were attributed to the presence of the C-O and C-C-O stretching vibration modes.…”

Section: Characterization Methodsmentioning

confidence: 98%

Stabilization of β-carotene embedded in a silica matrix and study of its physical properties

Martı́nez

Espericueta²,

Guerrero-Serrano

et al. 2020

Mater. Res. Express

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This work reports on the behavior of β-carotene within a silica matrix prepared by the sol-gel method. Results show that highly pure β-carotene integrates with the silica to form a silica-based composite. The interaction exhibited between the inorganic matrix and the β-carotene results in a π-d conjugated system that guarantees the development of the protective mechanism of the β-carotene and stabilizes the organic molecule, allowing its preservation at high calcination temperature. The spectroscopic analysis, made through fluorescence emission and infrared spectroscopy, shows the presence of βcarotene within the silica matrix after the composite was calcined at 1000°C. Furthermore, the structural interactions of the β-carotene with the silica and the protective function of the β-carotene change the crystallization route naturally followed by the silica when exposed to increasing temperature. In this case, the amorphous silica matrix is preserved after high-temperature calcination, which is beneficial for biomedical applications as it allows the release and transport of the β-carotene to take full advantage of its health benefits.

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Synthesis of SiO₂ nanopowders containing quartz and cristobalite phases from silica sands

Cited by 79 publications

References 22 publications

Gene to diagnostic: Self immobilizing protein for silica microparticle biosensor, modelled with sarcosine oxidase

Gene to diagnostic: Self immobilizing protein for silica microparticle biosensor, modelled with sarcosine oxidase

Exploring the use of silica sands and calcite from natural deposits to prepare bioactive glasses

Stabilization of β-carotene embedded in a silica matrix and study of its physical properties

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Synthesis of SiO2 nanopowders containing quartz and cristobalite phases from silica sands

Cited by 79 publications

References 22 publications

Gene to diagnostic: Self immobilizing protein for silica microparticle biosensor, modelled with sarcosine oxidase

Gene to diagnostic: Self immobilizing protein for silica microparticle biosensor, modelled with sarcosine oxidase

Exploring the use of silica sands and calcite from natural deposits to prepare bioactive glasses

Stabilization of β-carotene embedded in a silica matrix and study of its physical properties

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Synthesis of SiO₂ nanopowders containing quartz and cristobalite phases from silica sands