Induced crystallization of amorphous biosilica to cristobalite by silicatein

The synergistic interference effect of silica nanoparticles concentration and the wavelength of ELISA on the colorimetric assay of cell toxicity

The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay is the most common method for the determination of cell toxicity, but some factors limit the sensitivity of this method, such as pH. Less attention had been paid to the interference effect of optical and plasmonic properties of SiO₂ nanoparticles (NPs) in the wavelength range assigned to MTT. This study investigated the synergistic interference effect of SiO₂ NPs and wavelength on MTT assay for the first time. The examined variables included the type of SiO₂ NPs concentrations (1, 10, and 100 mM) and different wavelengths (470, 490, 520, and 570 nm). The results showed that optical density (OD) increased (p < 0.05) when wavelength and the concentration of crystalline SiO₂ NPs increased. So, the maximum OD at 10 and 100 mM were attributed to crystalline SiO₂ NPs (p < 0.05) due to the functional group, whereas it was related to amorphous at 1 mM (p > 0.05). According to polynomial regression modeling (PRM), the maximum interference effect was predicted at crystalline SiO₂ NPs and wavelength > 550 nm. Besides, the synergistic effects of SiO₂ NPs, wavelength, and concentration of NPs had been a good fitting with first-order PRM. Thus, the concentration of SiO₂ NPs had a confounder factor in colorimetric for MTT assay. The best artificial neural network (ANN) structure was related to the 3:7:1 network (R_all = 0.936, MSE = 0.0006, MAPE = 0.063). The correlation between the actual and predicted data was 0.88. As SiO₂ NPs presence is an interfering factor in MTT assay concerning wavelength, it is suggested wavelength use with minimum confounding effect for MTT assay.

The toxicity of SiO2 NPs on cell proliferation and cellular uptake of human lung fibroblastic cell line during the variation of calcination temperature and its modeling by artificial neural network

Less attention had been paid to cell toxicity of the various synthesis methods of nanoparticles, this study investigated the effect of the calcination temperature(CT) on the crystallization of SiO2 nanoparticles(NPs), cell proliferation(CP), and cellular uptake(CU) in MRC-5. In this study, parameters were adjusted as CT(70-1000 °C), calcination time(2, 12, and 24 h), and catalyst feed rate(0.01, 0.05, and 0.1 mL.min1). CP was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) test after a 24-h exposure. The CU was achieved using ICP-MS. Results were analyzed using MATLAB2018. Results revealed that the size of synthesized particles was lower than 50 nm and, the XRD peak varied from 21 to 30° during the increase in CT. FTIR spectra confirmed the existence of Si-O and Si-Cl bonds. The maximum level of crystallization was at 1000 °C. CP decreased with the rise in the concentration of NPs(p < 0.05), as well as an increase in feed rate. A positive relationship between increased crystallization and decreased CP(R = 0.78) was seen, while such a trend was not observed in calcination time. The suggested structure in this study was 4:10:1 with Rall = 0.97, Rtest = 0.97, RMSE = 0.25, and MSE = 0.003. Furthermore, the CU rate increased with the rise in CT and calcination time. The maximum and minimum CU levels were related to NPs calcinated in 1000 °C-24 h and 350 °C-2 h, respectively. As a consequence, the most toxicity of SiO2 NPs was related to the crystalline NP. Therefore, the increase in CT and the calcination time were significant factors affecting on crystallization of SiO2 NPs, CP of lung cell, as well as CU of SiO2.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40201-021-00663-4.

Diatoms Biomass as a Joint Source of Biosilica and Carbon for Lithium-Ion Battery Anodes

The biomass of one type cultivated diatoms (Pseudostaurosira trainorii), being a source of 3D-stuctured biosilica and organic matter-the source of carbon, was thermally processed to become an electroactive material in a potential range adequate to become an anode in lithium ion batteries. Carbonized material was characterized by means of selected solid-state physics techniques (XRD, Raman, TGA). It was shown that the pyrolysis temperature (600 °C, 800 °C, 1000 °C) affected structural and electrochemical properties of the electrode material. Biomass carbonized at 600 °C exhibited the best electrochemical properties reaching a specific discharge capacity of 460 mAh g-1 for the 70th cycle. Such a value indicates the possibility of usage of biosilica as an electrode material in energy storage applications.

Cristobalite and Hematite Particles in Human Brain

Foreign substances get into the internal environment of living bodies and accumulate in various organs. Cristobalite and hematite particles in the glial cells of pons cerebri of human brain with diagnosis of Behhet disease with scanning electron microscopy (SEM), energy-dispersive microanalysis (EDX), and transmission electron microscopy (TEM) with diffraction were identified. SEM with EDX revealed the matter of irregular micrometer-sized particles sometimes forming polyhedrons with fibrilar or stratified structure. It was found in some particles Ti, Fe, and Zn. Some particles contained Cu. TEM and electron diffraction showed particles of cristobalite and hematite. The presence of the particles can be a result of environmental effect, disruption of normal metabolism, and transformation of physiologically iron-ferrihydrite into more stable form-hematite. From the size of particles can be drawn the long-term accumulation of elements in glial cells.

Hierarchical architecture of sponge spicules: biocatalytic and structure-directing activity of silicatein proteins as model for bioinspired applications

Since the first description of the silicateins, a group of enzymes that mediate the formation of the amorphous, hydrated biosilica of the skeleton of the siliceous sponges, much progress has been achieved in the understanding of this biomineralization process. These discoveries include, beside the proof of the enzymatic nature of the sponge biosilica formation, the dual property of the enzyme, to act both as a structure-forming and structure-guiding protein, and the demonstration that the initial product of silicatein is a soft, gel-like material that has to undergo a maturation process during which it achieves its favorable physical-chemical properties allowing the development of various technological or medical applications. This process comprises the hardening of the material by the removal of water and ions, its cast-molding to specific morphologies, as well as the fusion of the biosilica nanoparticles through a biosintering mechanism. The discovery that the enzymatically formed biosilica is morphogenetically active and printable also opens new applications in rapid prototyping and three-dimensional bioprinting of customized scaffolds/implants for biomedical use.

Biomineralization-inspired synthesis of functional organic/inorganic hybrid materials: organic molecular control of self-organization of hybrids

Biomineralization-inspired synthesis of functional organic/inorganic hybrid materials. Molecularly controlled mechanisms of biomineralization and application of the processes towards future material synthesis are introduced.

Induced transformation of amorphous silica to cristobalite on bacterial surfaces

Phase transformation of amorphous silica to cristobalite at a relatively low temperature of 800 °C has been achieved on bacterial surfaces.