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Periasamy V.S.,Nanobiotechnology and Molecular Biology Research Laboratory | Athinarayanan J.,Nanobiotechnology and Molecular Biology Research Laboratory | Akbarsha M.A.,Nanobiotechnology and Molecular Biology Research Laboratory | Akbarsha M.A.,Bharathidasan University | And 2 more authors.
Applied Biochemistry and Biotechnology

The SiO2 synthesized in bulk form, adopting the conventional methods for application in food industry applications, may also contain nano-sized particles. On account of the unique physico-chemical properties, the SiO2 particulates, such as size and shape, cause metabolic toxicity in cells. Poor understanding of the molecular level nanotoxicity resulting from high-volume synthetic SiO2 exposures in humans is a serious issue, since these particles may also contribute to metabolic stress-mediated chronic diseases. In the present study, we examined the structural characteristics of these nano-sized silica particles adopting SEM and dynamic light scattering (DLS) and assessed the alterations in the cell cycle induced by these silica particles in human mesenchymal stem cells (hMSCs) adopting 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell viability assay, morphological changes in the cells adopting fluorescent microscopy, cell cycle analysis adopting flow cytometry, and the expression of genes linked to cell cycle (i.e., proliferating cell nuclear antigen (PCNA), early growth response protein (EGR1), E2F transcription factor (E2F1), cyclin D1, cyclin C, and cyclin D3) adopting qPCR. The SEM and DLS studies indicated that the commercial grade SiO2-NPs were in the nano-scale range. Alterations in the cytoplasmic organization, nuclear morphology, cell cycle progression, and expression of genes linked to cell cycle-dependent metabolic stress through EGR1, CCND, and E2F1 genes were the primary indicators of metabolic stress. Overall, the results of this study demonstrate that synthetic SiO2 acutely affects hMSC through cell cycle-dependent oxidative stress gene network. The toxicity mechanisms (both acute and chronic) of food grade silica should be investigated in greater depth with special reference to food safety. © 2014, Springer Science+Business Media New York. Source

Periasamy V.S.,Nanobiotechnology and Molecular Biology Research Laboratory | Athinarayanan J.,Nanobiotechnology and Molecular Biology Research Laboratory | Al-Hadi A.M.,Nanobiotechnology and Molecular Biology Research Laboratory | Juhaimi F.A.,Nanobiotechnology and Molecular Biology Research Laboratory | And 2 more authors.
Environmental Toxicology and Pharmacology

Food grade TiO2 (E171) is a synthetic additive, and widely used as a coloring agent in many foods, pharmaceutical and personal care products. A few reports have highlighted that insoluble particulates (less than 200nm) of food grade TiO2 are found in many foods and confectionary products. However, information regarding the physico-chemical properties (i.e., size and shape)-based food grade TiO2 nanotoxicity related human health issues are limited. The main goal of this study is to examine the presence of nano-sized particulates and its structural characteristics of food grade- TiO2 materials and to assess the acute cellular uptake and metabolic stress induced by these particulates in human lung fibroblast (WI-38) cells. The results of transmission electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction studies indicated that about food grade TiO2 sample contains spherical shaped particulate forms in the nano-scale range, <100nm. The intracellular oxidative stress in human lung fibroblast cells (WI-38) was assessed through studies investigating the cellular uptake of the particles, changes in nuclear and cytoplasmic morphology, intracellular ROS, mitochondrial trans-membrane potential, the cell cycle and the expression of genes linked to metabolic stress markers. Altogether our data clearly indicate that primary metabolic stress indicators such as changes in the intracellular ROS, the dose-dependent loss of the mitochondrial membrane potential, alterations in cell cycle progression (G2/M>S>G0/G1) and changes in the TNF and CYP1A gene expression pattern are linked to cellular stress. Thus, food grade TiO2 as nano-scaled contaminants could not only be potential human health risk factors, suggesting that safety considerations with special respect to a few crucial factors such as size, and shape should be considered and regulated by food regulators. © 2014 Elsevier B.V. Source

Alshatwi A.A.,Nanobiotechnology and Molecular Biology Research Laboratory | Athinarayanan J.,Nanobiotechnology and Molecular Biology Research Laboratory | Periasamy V.S.,Nanobiotechnology and Molecular Biology Research Laboratory
Materials Science and Engineering C

Synthetic forms of silica have low biocompatibility, whereas biogenic forms have myriad beneficial effects in current toxicological applications. Among the various sources of biogenic silica, rice husk is considered a valuable agricultural biomass material and a cost-effective resource that can provide biogenic silica for biomedical applications. In the present study, highly pure biogenic silica nanoparticles (bSNPs) were successfully harvested from rice husks using acid digestion under pressurized conditions at 120°C followed by a calcination process. The obtained bSNPs were subjected to phase identification analysis using X-ray diffraction, which revealed the amorphous nature of the bSNPs. The morphologies of the bSNPs were observed using transmission electron microscopy (TEM), which revealed spherical particles 10 to 30 nm in diameter. Furthermore, the biocompatibility of the bSNPs with human lung fibroblast cells (hLFCs) was investigated using a viability assay and assessing cellular morphological changes, intracellular ROS generation, mitochondrial transmembrane potential and oxidative stress-related gene expression. Our results revealed that the bSNPs did not have any significant incompatibility in these in vitro cell-based approaches. These preliminary findings suggest that bSNPs are biocompatible, could be the best alternative to synthetic forms of silica and are applicable to food additive and biomedical applications. © 2014 Elsevier B.V. All rights reserved. Source

Alshatwi A.A.,Nanobiotechnology and Molecular Biology Research Laboratory | Subbarayan P.V.,Nanobiotechnology and Molecular Biology Research Laboratory | Ramesh E.,Nanobiotechnology and Molecular Biology Research Laboratory | Al-Hazzani A.A.,King Saud University | And 2 more authors.
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment

An urgent need for toxicological studies on aluminium oxide nanoparticles (Al2O3 -NPs) has arisen from their rapidly emerging range of applications in the food and agricultural sectors. Despite the widespread use of nanoscale aluminium and its composites in the food industry, there is a serious lack of information concerning the biological activities of Al2O3 -NPs (ANPs) and their impact on human health. In this preliminary study, the effects of ANPs on metabolic stress in human mesenchymal stem cells (hMSCs) were analysed. The results showed dose-dependent effects, including cellular toxicity. The mitochondrial membrane potential in the hMSCs decreased with increasing ANP concentrations after 24 h of exposure. The expression levels of oxidative stress-responsive enzymes were monitored by RT-PCR. The expression levels of CYP1A and POR were up-regulated in response to ANPs, and a significant down-regulation in the expression of the antioxidant enzyme SOD was observed. Further, dose-dependent changes in the mRNA levels of GSTM3, GPX and GSR were noted. These findings suggest that the toxicity of ANPs in hMSCs may be mediated through an increase in oxidative stress. The results of this study clearly demonstrate the nanotoxicological effects of ANPs on hMSCs, which will be useful for nanotoxicological indexing. © 2013 Copyright Taylor and Francis Group, LLC. Source

Athinarayanan J.,Nanobiotechnology and Molecular Biology Research Laboratory | Periasamy V.S.,Nanobiotechnology and Molecular Biology Research Laboratory | Alhazmi M.,Nanobiotechnology and Molecular Biology Research Laboratory | Alshatwi A.A.,Nanobiotechnology and Molecular Biology Research Laboratory
Journal of Biomedical Materials Research - Part B Applied Biomaterials

Sugarcane bagasse is a fibrous material and an excellent bioresource for biogenic silica. Moreover, sugarcane bagasse has low production costs and is a sustainable precursor for the synthesis of biogenic silica nanoparticles (BSNPs). In this study, we synthesized BSNPs using sugarcane bagasse. The acid pretreatment of sugarcane was carried out in an autoclave, which eliminates metal ions and promotes the hydrolysis of organic substances. Residues of the acid pretreatment were incinerated at different temperatures to determine the role of temperature on the formation of BSNPs. The crystalline nature and morphology of the prepared BSNPs were analyzed using X-ray diffraction analysis and transmission electron microscopy. The X-ray diffraction analysis result indicates that the prepared BSNPs have an amorphous nature. Transmission electron microscopy images confirmed that the BSNPs have an irregular shape with a porous morphology. The biocompatibility of BSNPs was studied by assessing their effect on human lung fibroblast cell viability, morphology, mitochondrial function, reactive oxygen species, and gene expression. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays and microscopy studies suggested that BSNPs do not affect cell viability or morphology. BSNPs slightly affect the mitochondrial membrane potential at high doses. In addition, BSNPs decreased the percentage of human lung fibroblast cell in G1 and G2/M phases and increased the S population. These studies revealed that the BSNPs were biocompatible, indicating that they may be applicable for biomedical applications. © 2015 Wiley Periodicals, Inc. Source

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