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Tools and resources. Services for applicants Toolkit Track your application Event calendar Ask a question. Grants Calls for data Consultations Observers. Stakeholders Engagement platforms Engagement in risk assessment Calls for stakeholders Stakeholder registration Training Programme. Funding programmes Upcoming calls Knowledge Centre National funding opportunities. Titanium dioxide: E no longer considered safe when used as a food additive. Published :. Genotoxicity Assessment Genotoxicity refers to the ability of a chemical substance to damage DNA , the genetic material of cells.
Scientific opinion on the safety assessment of titanium dioxide as a food additive E What is titanium dioxide? Researchers are discovering new potential uses for titanium dioxide in this form. This includes clean energy production.
As a photocatalyst, it has also been shown that TiO 2 can carry out hydrolysis breaking water into hydrogen and oxygen , and the collected hydrogen can be used as a fuel.
Visit uses of titanium dioxide for more information. Titanium dioxide has a number of unique characteristics that make it ideally suited to many different applications. TiO 2 is also an insulator. Importantly, titanium dioxide also has a very high refractive index its ability to scatter light , even higher than diamond.
This makes it an incredibly bright substance and an ideal material for aesthetic design use. Another crucial property of titanium dioxide is that it can show photocatalytic activity under UV light.
This makes it effective for environmental purification, for different kinds of protective coatings, sterilisation and anti-fogging surfaces, and even in cancer therapy. TiO 2 possesses different qualities depending on whether it is produced as pigment-grade or nanomaterial-grade. Both forms are tasteless, odourless and insoluble. Pigment-grade TiO 2 particles are approximately nm in dimension and this form accounts for 98 percent of total production.
Nano, or ultrafine TiO 2 comprises of primary particles sized less than nm. In this grade, titanium dioxide is transparent colourless and boasts improved UV scattering and absorbing properties compared with larger particle-size, pigment-grade TiO 2.
Titanium is one of the most common metals on earth, but it does not occur naturally in this elemental form. Titanium dioxide — also known as titanium IV oxide or titania — is the naturally occurring compound created when titanium reacts with the oxygen in the air. It also found with other elements, including calcium and iron. Its chemical formula is TiO 2 , which means it consists of one titanium atom and two oxygen atoms hence dioxide. Titanium dioxide itself was officially first named and created in a laboratory in the late s.
Taken together, the overall exposure of an average individual TiO 2 NPs is not known; there are still opened questions regarding toxicokinetics and specific organ toxicity of TiO 2 NPs, in particular at oral and dermal exposure, and thus it is impossible to make a reliable quantitative risk assessment. One of the main observations of this review is that, due to the versatility of the TiO 2 NPs in terms of particle size, shape, crystal structure, dispersion in biological surroundings bioavailability and UV-induced photocatalytic activity, no single conclusion can be drawn, since different forms of TiO 2 may act very differently.
Until we know more, in our opinion TiO 2 NPs should be used with great care, in particular in food and cosmetics. The least that should be done for the consumer is that a declaration of nano-sized TiO 2 in these products is obligatory, so that we will have the choice whether to use it or not. We thank Prof. Roger Pain and Assist. Paul McGuiness for critical reading of the manuscript. Authors would also like to thank Dr. National Center for Biotechnology Information , U.
Journal List Radiol Oncol v. Radiol Oncol. Published online Nov Author information Article notes Copyright and License information Disclaimer. Received Oct 7; Accepted Oct This article has been cited by other articles in PMC. Abstract Background Titanium dioxide TiO 2 is considered as an inert and safe material and has been used in many applications for decades.
Conclusions Until relevant toxicological and human exposure data that would enable reliable risk assessment are obtained, TiO 2 nanoparticles should be used with great care. Keywords: titanium dioxide, nanoparticles, toxicity, applications, safety. Introduction Titanium dioxide titania, TiO 2 is chemically inert, semiconducting material that also exhibits photocatalytic activity in the presence of light with an energy equal to or higher than its band-gap energy. Chemical and physical properties of TiO 2 nanoparticles Nanoparticles NPs are generally defined as particles having at least one dimension smaller than nm.
Open in a separate window. Mechanisms of TiO 2 NPs toxicity As already discussed, the physicochemical properties of particles depend on their size, so that, at the nanometre level, the material is chemically more reactive. Oxidative stress induced by TiO 2 NPs Oxidative stress is thought to be a key mechanism responsible for adverse biological effects exerted by NPs. Genotoxicity of TiO 2 NPs Several studies show that nano-TiO 2 induces ge-notoxic effects, including DNA damage, and micronuclei formation that is indicative of chromosomal aberrations in different cell lines 32 , 35 — 38 The studies also showed that genotoxic effects elicited NPs strongly depended upon their size by TiO 2 and form.
Immunotoxic effects of TiO 2 NPs Depending on physicochemical properties of NPs, they are recognized and taken up by immune cells, such as macrophages, monocytes, platelets, leuko-cytes and dendritic cells, and can trigger an inflammatory response. Neurotoxic effects of TiO 2 NPs It has been reported that inhaled NPs can translocate to the central nervous system through the olfactory pathway 22 and by crossing the blood-brain barrier.
TiO 2 NPs in everyday life Nano-sized TiO 2 in various forms is used widely in everyday life in a variety of products, such as anti-fouling paints, household products, plastic goods, medications, cosmetics, sunscreens, pharmaceutical additives and food colorants, and many new applications are under development or already in pilot production.
Dermal exposure to TiO 2 NPs TiO 2 NPs as a component of the sunscreen-technology revolution During recent decades, skin cancer has become the most frequent neoplastic disease among the Caucasian population in Europe, North America and Australia, and its incidence has reached epidemic proportions. Cytotoxic and genotoxic effects of TiO 2 NPs in dermal cells and skin models Different dermal cell types have been reported to differ in their sensitivity to nano-sized TiO 2.
TiO 2 NPs intake by food TiO 2 has been well accepted in the food industry and can be found as the E additive in various food products, mainly for whitening and texture. Exposure to TiO 2 NPs by inhalation Inhalation exposure to TiO 2 particles occurs pre-dominantly in occupational settings during production of TiO 2 powders and manufacturing the products containing TiO 2.
Human epidemiological studies Several case reports described adverse health effects in workers with potential TiO 2 exposure that later lead to epidemiological studies of a relationship between occupational exposure and observed cases. Exposure to TiO 2 NPs through body implants A few-nanometres-thick layer of amorphous TiO 2 is commonly formed on the surface of orthopaedic and dental implants made of titanium metal or its alloys.
Environmental pollution by TiO 2 NPs Toxic effects of TiO 2 NPs on aquatic organisms The trend in the production of NPs is likely to lead to increasing amounts of nano-powders in the air, water and soil, which will consequently affect living organisms.
The effects of TiO 2 NPs in plants In addition to the toxic effects of TiO 2 NPs, discussed in previous chapters, these NPs have been also shown to promote photosynthesis and nitrogen metabolism, resulting in the enhanced growth of spinach. Potential desirable effects of TiO 2 NPs The same properties of nano-sized TiO 2 that are associated with undesirable, harmful effects can be exploited for certain useful applications.
Where we are and where to go The mechanistic toxicological studies showed that TiO 2 NPs induced adverse effects are predominantly mediated by oxidative stress, which may lead to cell damage, genotoxic effects, inflammatory responses and changes in cell signalling. References 1. Analysis of titanium pigments in human lung tissue. Scand J Work Environ Health. The comparison of a fibrogenic and two nonfibrogenic dusts by bronchoalveolar lavage.
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