The present opinion deals with an updated safety assessment of the food additive titanium dioxide (E 171) based on new relevant scientific evidence considered by the Panel to be reliable, including data obtained with TiO2 nanoparticles (NPs) and data from an extended one-generation reproductive toxicity (EOGRT) study. Less than 50% of constituent particles by number in E 171 have a minimum external dimension 30 nm) up to the highest dose tested of 100 mg/kg bw per day. No effects on reproductive and developmental toxicity were observed up to a dose of 1,000 mg E 171/kg bw per day, the highest dose tested in the EOGRT study. However, observations of potential immunotoxicity and inflammation with E 171 and potential neurotoxicity with TiO2 NPs, together with the potential induction of aberrant crypt foci with E 171, may indicate adverse effects. With respect to genotoxicity, the Panel concluded that TiO2 particles have the potential to induce DNA strand breaks and chromosomal damage, but not gene mutations. No clear correlation was observed between the physico-chemical properties of TiO2 particles and the outcome of either in vitro or in vivo genotoxicity assays. A concern for genotoxicity of TiO2 particles that may be present in E 171 could therefore not be ruled out. Several modes of action for the genotoxicity may operate in parallel and the relative contributions of different molecular mechanisms elicited by TiO2 particles are not known. There was uncertainty as to whether a threshold mode of action could be assumed. In addition, a cut-off value for TiO2 particle size with respect to genotoxicity could not be identified. No appropriately designed study was available to investigate the potential carcinogenic effects of TiO2 NPs. Based on all the evidence available, a concern for genotoxicity could not be ruled out, and given the many uncertainties, the Panel concluded that E 171 can no longer be considered as safe when used as a food additive.

Safety assessment of titanium dioxide (E171) as a food additive

Novel Mo-doped WO3/ZnO nanocomposites loaded with polyvinyl alcohol towards efficient visible-light-driven photodegradation of methyl orange

Bioactive plant chemicals are considered to be rich and useful for creating nanomaterials. The current work investigated the biosynthesis of silver nanoparticles (AgNPs) using ethanolic flaxseed extract as an efficient reducing factor. The production of AgNPs was verified by color-shifting observation of the mixture of silver nitrate (AgNO3) from yellow to a reddish suspension after the addition of the extract and by evaluating it by UV–visible inspection. Additionally, FTIR spectrum was used to support the identification of functional groups. The morphology and structure of AgNPs were assessed using scanning electron microscopy (SEM), and X-ray diffraction (XRD) examinations, which revealed spherical AgNPs with a diameter of 46.98 ± 12.45 nm and a crystalline structure. The zeta potential (ZP) and dynamic light scattering (DLS) measurements of AgNPs revealed values of −44.5 mV and 231.8 nm, respectively, suggesting appropriate physical stability. The antibacterial activity of AgNPs was investigated against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and Streptococcus pyogenes, while the antioxidant effect was investigated using the DPPH technique. These obtained AgNPs could potentially be used as efficient antibacterial and antioxidant nanomaterials.

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Green Synthesis and Characterization of Silver Nanoparticles Using Flaxseed Extract and Evaluation of Their Antibacterial and Antioxidant Activities

Herein, the aqueous extract of Portulaca oleracea has been used as a safe, cheap, eco-friendly, and applicable scale-up method to bio-fabricate copper oxide nanoparticles (CuO-NPs). The character of CuO-NPs were determined using UV-vis spectroscopy, Fourier transform infrared (FT-IR), X-ray diffraction (XRD), Transmission electron microscopy (TEM), Energy dispersive X-ray(EDX), Dynamic light scattering (DLS), and zeta potential. Spherical and crystalline CuO-NPs with a size range of 5–30 nm at a maximum surface plasmon resonance of 275 nm were successfully fabricated. The main components of the green-synthesized particles were Cu and O with weight percentages of 49.92 and 28.45%, respectively. A Zeta-potential value of −24.6 mV was recorded for CuO-NPs, indicating their high stability. The plant-based CuO-NPs showed promising antimicrobial and catalytic activity in a dose-dependent manner. Results showed that the synthesized CuO-NPs had the efficacy to inhibit the growth of pathogens Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans with low MIC values in the ranges of 6.25–25 µg/mL. The highest decolorization percentages of tanning wastewater were attained under sunlight irradiation conditions at a concentration of 2.0 mg/mL after 200 min with percentages of 88.6 ± 1.5% compared to those which were recorded under dark conditions (70.3 ± 1.2%). The physicochemical parameters of tanning wastewater including total suspended solids (TSS), total dissolved solids (TDS), chemical oxygen demand (COD), biological oxygen demand (BOD), and conductivity under optimum conditions were significantly decreased with percentages of 95.2, 86.7, 91.4, 87.2, and 97.2%, respectively. Interestingly, the heavy metals including cobalt (Co), lead (Pb), nickel (Ni), cadmium (Cd), and chromium (Cr (VI)) decreased with percentages of 73.2, 80.8, 72.4, 64.4, and 91.4%, respectively, after treatment of tanning wastewater with CuO-NPs under optimum conditions. Overall, the plant-synthesized CuO-NPs that have antimicrobial and catalytic activities are considered a promising nano-catalyst and environmentally beneficial to wastewater treatment.

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Plant-Based Copper Oxide Nanoparticles; Biosynthesis, Characterization, Antibacterial Activity, Tanning Wastewater Treatment, and Heavy Metals Sorption

Novel molybdenum (Mo)-doped nickel oxide (NiO) Nanoparticles (NPs) were synthesized by using a simple sonochemical methodology and the synthesized NPs were investigated for antioxidant, and antibacterial applications. The X-ray diffraction (XRD) analysis revealed that the crystal systems of rhombohedral (21.34 nm) and monoclinic (17.76 nm) were observed for pure NiO and Mo-doped NiO NPs respectively. The scanning electron microscopy (SEM) results show that the pure NiO NPs possess irregular spherical shape with an average particle size of 93.89 nm while the Mo-doped NiO NPs exhibit spherical morphology with an average particle size of 85.48 nm. The ultraviolet-visible (UV-Vis) spectrum further indicated that the pure and Mo-doped NiO NPs exhibited strong absorption band at the wavelengths of 365 and 349 nm, respectively. The free radical scavenging activity of NiO and Mo-doped NiO NPs was also investigated by utilizing several biochemical assays. The Mo-doped NiO NPs showed better antioxidant activity (84.2%) towards ABTS. + at 200 µg/mL in comparison to their pure counterpart which confirmed that not only antioxidant potency of the doped NPs was better than pure NPs but this efficacy was also concentration dependant as well. The NiO and Mo-doped NiO NPs were further evaluated for their antibacterial activity against gram-positive (Staphylococcus aureus and Bacillus subtilis) and gram-negative (Pseudomonas aeruginosa and Escherichia coli) bacterial strains. The Mo-doped NiO NPs displayed better antibacterial activity (25 mm) against E. coli in comparison to the pure NPs. The synthesized NPs exhibited excellent aptitude for multi-dimensional applications. 

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Effect of Mo doping in NiO nanoparticles for structural modification and its efficiency for antioxidant, antibacterial applications

Abstract Zinc oxide-silver (ZnO–Ag), and zinc oxide-gold (ZnO–Au) nano-composites were prepared through wet chemical process and laced into single-walled carbon nanotubes (SWCNTs) to yield ZnO–Ag-SWCNTs, and ZnO–Au-SWCNTs hybrids. These nano-composite-laced SWCNTs hybrids were characterized using Raman spectroscopic, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analyses. The hybrids were evaluated for their effects on phagocytic cells and bactericidal activity against the gram-negative bacteria E. coli. Their phagocytic cell activities and intracellular killing actions were found to be significantly increased, as the ZnO–Ag-SWCNTs and ZnO–Au-SWCNTs nano-hybrids induced widespread clearance of Escherichia coli. An increase in the production of reactive oxygen species (ROS) also led to upregulated phagocytosis, which was determined mechanistically to involve the phagocyte NADPH oxidase (NOX2) pathway. The findings emphasized the roles of ZnO–Ag- and ZnO–Au-decorated SWCNTs in the prevention of bacterial infection by inhibiting biofilm formation, showing the potential to be utilized as catheter coatings in the clinic. 

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Modification of SWCNTs with hybrid materials ZnO–Ag and ZnO–Au for enhancing bactericidal activity of phagocytic cells against Escherichia coli through NOX2 pathway

This study investigated for the first time a simple bio-synthesis approach for the synthesis of copper oxide nanoparticles (CuO NPs) using Annona muricata L (A. muricata) plant extract to test their anti-cancer effects. The presence of CuONPs was confirmed by UV-visible spectroscopy, Scanning electron microscope (SEM), and Transmission electron microscope (TEM). The antiproliferative properties of the synthesized nanoparticles were evaluated against (AMJ-13), (MCF-7) breast cancer cell lines, and the human breast epithelial cell line (HBL-100) as healthy cells. This study indicates that CuONPs reduced cell proliferation for AMJ-13 and MCF-7. HBL-100 cells were not significantly inhibited for several concentration levels or test periods. The outcomes suggest that the prepared copper oxide nanoparticles acted against the growth of specific cell lines observed in breast cancer. It was observed that cancer cells had minor colony creation after 24 h sustained CuONPs exposure using (IC50) concentration for AMJ-13 was (17.04 µg mL-1). While for MCF-7 cells was (18.92 µg mL-1). It indicates the uptake of CuONPs by cancer cells, triggering apoptosis. Moreover, treatment with CuONPs enhanced Lactate dehydrogenase (LDH) production, probably caused by cell membrane damage, creating leaks comprising cellular substances like lactate dehydrogenase. Hence, research results suggested that the synthesized CuONPs precipitated anti-proliferative effects by triggering cell death through apoptosis. 

/pdf/biosynthesis-of-copper-oxide-nanoparticles-mediated-annona-1p3iqou7.pdf

Biosynthesis of copper oxide nanoparticles mediated Annona muricata as cytotoxic and apoptosis inducer factor in breast cancer cell lines

This study assay the toxic effects of titanium dioxide nanoparticles (TiO2NPs) on peripheral blood lymphocytes and Hep-2 cell by measuring Mitotic Index (MI), Blastogenic Index (BI), Total Chromosomal Aberration (TCA) and growth rate of cancer cells. TiO2NPs were synthesized using laser technique by ablation of titanium target immersed in distilled de-ionized water (DDW) using Q-switched pulsed Nd:YAG laser with repetition rate of 1 Hz, wavelength of 1064 nm, 300 pulses and energy of 400 mJ. Chromosomal analyses were carried out at different concentrations of synthesized TiO2 NPs (0.0, 45, 90, and 180) µg/mL. X-ray diffraction (XRD) exhibited anatase phase of prepared TiO2NPs and showed that the crystalline structures of TiO2NPs is tetragonal. Absorption spectrum of TiO2 NPs was at ultraviolet-region 215 nm due to Surface Plasmon Resonance (SPR), and the particles size distribution of the prepared TiO2NPs ranged from 40 to 110 nm. Finding showed that both MI and BI suffered from high reduction while TCA suffered from significant elevation represented by Chromatid Breaks (CB), Micronuclei (MN) and Ring Chromosome (RC). The highest proportion of (TCA) has been observed in 180 µg/mL of TiO2NPs, (significant at p ≤ 0.05). while the toxic effects of prepared TiO2NPs on Hep-2 cell line represent decline in growth rate with an increase in concentration of TiO2NPs with malformation in the cell structure and shape and placement of the nucleus. The ablation via Q-switched Nd: YAG laser has adequacy to prepare TiO2NPs with 215 nm absorption spectrum, nearly spherical particles and suitable particle size (40–110 nm). In vitro assay showed that prepared TiO2 NPs have significant cytotoxic effects on peripheral blood lymphocyte and Hep-2 cell line by reduction in both Mitotic index (MI) and blastogenic index (BI) and growth rate of cancer cells.

Cytotoxic Effects of Titanium Dioxide Nanaoparticles Synthesized by Laser Technique on Peripheral Blood Lymphocytes and Hep-2 Cell Line

https://ijocaas.com/wp-content/uploads/2017/01/IJOCAAS-02-01-002-Feb2017.pdf

Antimicrobial Activity of TiO2 NPs against Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923

Nanomaterials and nanostructures have shown fascinating performances in various biomedicine fields, from cosmetic to cancer diagnosis and therapy. Engineered nanomaterials can encapsulate both lipophilic and hydrophilic substances/drugs to eliminate their limitations in the free forms, such as low bioavailability, multiple drug administration, off-target effects, and various side effects. Moreover, it is possible to deliver the loaded cargo to the desired site of action using engineered nanomaterials. One approach that has made nanocarriers more sophisticated is the "biomimetic" concept. In this scenario, biomolecules (e.g., natural proteins, peptides, phospholipids, cell membranes) are used as building blocks to construct nanocarriers and/or modify agents. For instance, it has been reported that specific cells tend to migrate to a particular site during specific circumstances (e.g., inflammation, tumor formation). Employing the cell membrane of these cells as a coating for nanocarriers confers practical targeting approaches. Accordingly, we introduce the biomimetic concept in the current study, review the recent studies, challenge the issues, and provide practical solutions. 

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Ruaa H. Abbas

Papers

Modification of SWCNTs with hybrid materials ZnO–Ag and ZnO–Au for enhancing bactericidal activity of phagocytic cells against Escherichia coli through NOX2 pathway

Biosynthesis of copper oxide nanoparticles mediated Annona muricata as cytotoxic and apoptosis inducer factor in breast cancer cell lines

Cytotoxic Effects of Titanium Dioxide Nanaoparticles Synthesized by Laser Technique on Peripheral Blood Lymphocytes and Hep-2 Cell Line

Antimicrobial Activity of TiO2 NPs against Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923

Implications of biomimetic nanocarriers in targeted drug delivery