Since silver nanoparticles act in cleaning biological stains and smells by producing hydroxyl and other oxygen radicals, which are toxic in vivo, then if they were ingested the consequences could be dire.

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Much of the damage looks like the result of oxidation by free radicals (oxygen-rich compounds released during cellular energy production).

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These free radicals are oxygen-rich molecules in which one of the oxygen atoms is particularly likely to react with other chemicals.

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Such reactions, though, often create damaging oxygen-rich molecules called free radicals, which are thought to be one of the driving forces of ageing.

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They then have nowhere to put all the light energy they are absorbing, and the resulting breakdown of biochemical pathways creates toxic oxygen-containing molecules known as free radicals.

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