Nanoparticles used in common household items caused genetic damage in mice

Nov 16, 2009

Titanium dioxide (TiO2) nanoparticles, found in everything from cosmetics to sunscreen to paint to vitamins, caused systemic genetic damage in mice, according to a comprehensive study conducted by researchers at UCLA's Jonsson Comprehensive Cancer Center.

The TiO2 nanoparticles induced single- and double-strand DNA breaks and also caused chromosomal damage as well as , all of which increase the risk for . The UCLA study is the first to show that the nanoparticles had such an effect, said Robert Schiestl, a professor of pathology, radiation oncology and environmental health sciences, a Jonsson Cancer Center scientist and the study's senior author.

Once in the system, the TiO2 nanoparticles accumulate in different organs because the body has no way to eliminate them. And because they are so small, they can go everywhere in the body, even through cells, and may interfere with sub-cellular mechanisms.

The study appears this week in the journal Cancer Research.

In the past, these TiO2 nanoparticles have been considered non-toxic in that they do not incite a chemical reaction. Instead, it is surface interactions that the nanoparticles have within their environment- in this case inside a mouse - that is causing the genetic damage, Schiestl said. They wander throughout the body causing oxidative stress, which can lead to .

It is a novel mechanism of toxicity, a physicochemical reaction, these particles cause in comparison to regular chemical toxins, which are the usual subjects of toxicological research, Schiestl said.

"The novel principle is that titanium by itself is chemically inert. However, when the particles become progressively smaller, their surface, in turn, becomes progressively bigger and in the interaction of this surface with the environment oxidative stress is induced," he said. "This is the first comprehensive study of titanium dioxide nanoparticle-induced genotoxicity, possibly caused by a secondary mechanism associated with inflammation and/or oxidative stress. Given the growing use of these nanoparticles, these findings raise concern about potential health hazards associated with exposure."

The manufacture of TiO2 nanoparticles is a huge industry, Schiestl said, with production at about two million tons per year. In addition to paint, cosmetics, sunscreen and vitamins, the nanoparticles can be found in toothpaste, food colorants, nutritional supplements and hundreds of other personal care products.

"It could be that a certain portion of spontaneous cancers are due to this exposure," Schiestl said. "And some people could be more sensitive to nanoparticles exposure than others. "I believe the toxicity of these nanoparticles has not been studied enough."

Schiestl said the nanoparticles cannot go through skin, so he recommends using a lotion sunscreen. Spray-on sunscreens could potentially be inhaled and the nanoparticles can become lodged in the lungs.

The mice were exposed to the TiO2 nanoparticles in their drinking water and began showing on the fifth day. The human equivalent is about 1.6 years of exposure to the nanoparticles in a manufacturing environment. However, Schiestl said, it's not clear if regular, everyday exposure in humans increases exponentially as continued contact with the nanoparticles occurs over time.

"These data suggest that we should be concerned about a potential risk of cancer or genetic disorders especially for people occupationally exposed to high concentrations of nanoparticles, and that it might be prudent to limit their ingestion through non-essential drug additives, food colors, etc.," the study states.

Next, Schiestl and his team will study exposure to the nanoparticles in mice that are deficient in DNA repair, to perhaps help find a way to predict which people might be particularly sensitive to them.

Source: University of California - Los Angeles

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User comments : 11

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not rated yet Nov 16, 2009
Quick we must trun ourselfs into computers so we can avoid this!!!
not rated yet Nov 16, 2009
Titanium Dioxide is a powerfull catalyst used in many chemical reactions.

Ive been saying this for years.
2 / 5 (2) Nov 16, 2009
I am in my 40's and titanium dioxide has been a coloring ingrediant as far back as I can remember. If it has not cased any substantiated problem by now, there probably will never be.(in humans)This is something that should not be worried about.
not rated yet Nov 16, 2009
Well imagine that!!! Its not too hard to figure out that Nano particles are a type of poison to the human body.

I predict that next they're going to say that genetically modified food causes death.
not rated yet Nov 16, 2009
OK so I'm totally open to nanotechnology and all this awesome technology that's coming out, however if it has negative implications like this, what are they planning on doing to stop them?
not rated yet Nov 16, 2009
Oh look Mommy! I made a wrench so small I can throw it into my cell's mechanics.

Jokes aside, Would making the particles a little bigger degrade their benefits to the products they are in? Most articles about this say that the size of the nano particle makes a big difference.
1 / 5 (1) Nov 16, 2009
I'm with you on this one, Dr_Righteous. Smoking doesn't hurt anyone either, people have been doing it since the beginning of time.
5 / 5 (1) Nov 17, 2009
I am in my 40's and titanium dioxide has been a coloring ingrediant as far back as I can remember. If it has not cased any substantiated problem by now, there probably will never be.(in humans)This is something that should not be worried about.

It's not titanium dioxide it's titanium dioxide *nanoparticles* which are toxic. Titanium dioxide in the form of single molecules or large particles is most likely safe, it's only problematic when it is too large to handle for ionic pumps and chelators which normally detoxify such compounds and at the same time small enough to freely pass through cell membranes. The actual size range where these requirements are met is quite small - about 1-100 nm but this is exactly the size of most manufactured nanoparticles.
not rated yet Nov 17, 2009
I advise everyone to avoid nanoparticles as much as possible, this study is just one of many showing serious health hazards associated with exposure to them (though may be first for TiO) and what we know is still likely only a tip of the iceberg.

Many nanoparticles (although apparently not TiO according to the article) freely pass through skin and enter cells where they interfere with cellular processes by binding to macromolecules. Our bodies don't have efficient ways of removing them so they just accumulate causing inflammation and increasing risk of health problems including cancer. Wikipedia has some good info on the subject with references http://en.wikiped...xicology

In vast majority of cases the health risk associated with nanoparticles far outweighs any benefits they offer so avoiding products which contain them is the best course of action. What is desperately needed is a law mandating a warning label on all products containing nanoparticles.
2.3 / 5 (4) Nov 17, 2009
It sounds like this ingredient is pervasive, does anyone know of a complete list of the products containing it?

As to...

"Smoking doesn't hurt anyone either, people have been doing it since the beginning of time."

Believe what you like, but please at least be responsible enough to delete your "stupid gene" from the world by not having children.
1 / 5 (2) Nov 18, 2009

You can assume anything that is white does contain titanium dioxide. That includes all periodicals paper, any white sweets, even skimmed milk!

Wikipedia: "Titanium dioxide accounts for 70% of the total production volume of pigments worldwide. It is widely used to provide whiteness and opacity to products such as paints, plastics, papers, inks, foods, and toothpastes. It is also used in cosmetic and skin care products, and it is present in almost every sunblock, where it helps protect the skin from ultraviolet light.

The findings of the IARC are based on the discovery that high concentrations of pigment-grade (powdered) and ultrafine titanium dioxide dust caused respiratory tract cancer in rats exposed by inhalation and intratracheal instillation."

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