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The Ingestion Pathway
Published in Antonietta Morena Gatti, Stefano Montanari, Advances in Nanopathology From Vaccines to Food, 2021
Antonietta Morena Gatti, Stefano Montanari
Titanium dioxide is probably the material most nanoparticles added to food are made of, and it is hard to tell how much of it we ingest daily. Those particles are not soluble in water and have three natural forms: rutile, anatase and brookite. Rutile and anatase particles are used to produce pigment-grade material for the colouring of some foods and may be coated with various materials (aluminium, silicon or polymers) to enhance their technological properties. Those coatings are made because they modify the reactions between the surface of the titanium dioxide particles and the matrix where they are mixed, resulting in lower aggregation and a better dispersion possibility (Fig. 5.13).
Bio-Ceramics for Tissue Engineering
Published in Naznin Sultana, Sanchita Bandyopadhyay-Ghosh, Chin Fhong Soon, Tissue Engineering Strategies for Organ Regeneration, 2020
Hasan Zuhudi Abdullah, Te Chuan Lee, Maizlinda Izwana Idris, Mohamad Ali Selimin
Gel oxidation is a thermochemical method to produce porous but well adhered layers of titania on titanium metal. The oxidation of these layers has changed the structure and phases of the titanium surface (anatase, rutile, and residual sodium titanate). The different titania polymorphs and sodium titanate contribute to the degree of hydroxyapatite precipitation during soaking in simulated body fluid. Precipitation of hydroxyapatite increases by irradiation with UV light. Photocatalytic properties of titania enhanced the surface reaction resulting in precipitation with more hydroxyapatite on the gel-oxidised Ti. The gel-oxidised surface showed good cell attachment and penetration in the majority of the cells. The appearance of this cell growth indicated that gel-oxidised Ti can provide a superior implant owing to good ceramic-cell adhesion.
Screening Smokes: Applications, Toxicology, Clinical Considerations, and Medical Management *
Published in Brian J. Lukey, James A. Romano, Salem Harry, Chemical Warfare Agents, 2019
Lawrence A. Bickford, Harry Salem
Chemistry and generation. Titanium dioxide is an obscurant used in bursting grenades to provide a temporary visible obscurant screen. Its primary use is as a low-toxicity alternative obscurant for training and as an instant screening hand smoke grenade. Titanium dioxide is a white pigment used in the paint industry and is very efficient at scattering visible light. The rutile form of titania has an optimum diameter of 0.25 µm for maximum extinction (Embury et al., 1994). In practice, aerosol dissemination of titania is over 1 µm using sonic nozzle dissemination (Delacy et al., 2011).
Application of titanium dioxide (TiO2) nanoparticles in cancer therapies
Published in Journal of Drug Targeting, 2019
Selin Çeşmeli, Cigir Biray Avci
TiO2 is a white, odourless and non-combustible powder. There are many different names for titanium dioxide such as titanium (IV) oxide, titania, titanic acid anhydride and Ti white. Titanium dioxide has two crystal structures; these are rutile and anatase which is more chemically active. Rutile form of titanium dioxide nanoparticles are also named as titanium dioxide fine particles (FP). As the anatase crystal structure increases, production of reactive oxygen species increases, too. Therefore, it is thought that the anatase titanium dioxide is more toxic to healthy cells than the rutile titanium dioxide. The rutile titanium dioxide is considered as chemically inert but when the particles become smaller, the surface area will increase and therefore the rutile titanium dioxide particles can become harmful according to the studies. Also, the modifications that are done on the surface of nanoparticles cause changes in the activity of titanium dioxide particles [10].
Nanoparticle-loaded microcapsules providing effective UV protection for Cry1Ac
Published in Journal of Microencapsulation, 2021
Yongjing Zhang, Aijing Zhang, Mengyuan Li, Kanglai He, Shuyuan Guo
TiO2 occurs as three polymorphs: rutile, anatase, and brookite. Due to the difficulty in its synthesis, brookite is used less frequently as functional material (Reyes-Coronado et al. 2008). However, anatase exhibits a higher photoactivity compared to rutile TiO2. The strong photocatalytic effect under UV-irradiation of anatase particles can induce many strong oxidising free radicals, which can simultaneously break protein inevitably (Qi et al. 2011). So rutile was used as a UV absorber in this experiment. But nano-TiO2 is more likely to agglomerate during the adsorption process and cannot be adsorbed on the surface of microcapsules by mechanical agitation. Cs has a stable ‘stereo’ effect which can enhance the stability of nanoparticles in solution and avoid reunite (Jiang et al. 2016). In the experiment of preparing silver nanoparticles, Cs was used to stabilise the nanoparticles as it prevented the Ag clusters from aggregation at the macroscopic level due to the ion-dipole intermolecular forces (Reicha et al. 2012). Besides, Cs can be used as a dispersant to modify the commonly used materials (Kim et al. 2007). So the coating material Cs is consequently added as the dispersant of nano-TiO2 to solve the problem. TiO2-Cs composite material has the following two advantages. Firstly, it does not need to consider the environmental damage and biological toxicity caused by its addition because it is non-toxic and rapidly biodegradable (Muzzarelli 2009, Jiang et al. 2016). Secondly, TiO2-Cs can be adsorbed on the surface of the microcapsule with Alg as the outermost coating material by electrostatic interaction, since Cs has the opposite charge to Alg.
Material-specific properties applied to an environmental risk assessment of engineered nanomaterials – implications on grouping and read-across concepts
Published in Nanotoxicology, 2019
The total production volume of nano-TiO2 has a mean of 10'250 metric tons (Sun et al. 2014). The allocation of the production volume to the product categories was based on the photocatalytic activity or stability of nano-TiO2 (anatase) or nano-TiO2 (rutile), respectively. The allocation of the applications to the corresponding nano-form is shown in Table S1. Following the applied allocation scheme, anatase nano-TiO2 represented 2'750 metric tons (27%) and rutile nano-TiO2 7'500 metric tons (73%) of the total production volume. With this separation among applications, two separate material flow diagrams for both forms of nano-TiO2 could be constructed (cf. Figure 1). The main application of rutile was assumed in cosmetics (59%) as a down-the-drain product that was released to wastewater during use. This resulted in 5'500 metric tons of rutile going through wastewater. Compared to anatase with 5 metric tons, rutile has a high direct release of 370 metric tons to surface waters mainly due to the use in sunscreens. Most of the wastewater fraction is treated in the wastewater treatment plant (WWTP). Because of the high WWTP removal efficiency, the majority of rutile ended up in the sewage sludge that is subsequently used as fertilizer to some extent. Thus, the most relevant sinks for rutile were the compartments sludge treated soil (1'600 metric tons), surface water (2'100 metric tons) as well as landfill (2'200 metric tons) as it is depicted in Figure 1. In contrast to rutile, the main applications of anatase were paints with a share of 8%, electronics with 7% and filters with 6%. These product categories mainly comprised applications with ENMs embedded in a matrix. Consequently, their environmental releases during usage were low and the compartments receiving most of the flows from production, manufacturing and consumption (PMC) were landfill (960 metric tons) and recycling/WMS for further treatment (650 metric tons).