For his doctoral dissertation Niskanen has been studying several hybrid nanomaterials, i.e. combinations of synthetic polymers and inorganic (gold, silver and montmorillonite) nanoparticles. He will defend his doctoral thesis at the University of Helsinki in April.
Part of the magic of nano-science is that on the scale of a billionth of a metre, matter and materials behave in ways that are not yet known. Neither is it always known what types of effects the nano version of the parent matter will have on its environment.
"Due to the fact that silver in nanoparticle form is bactericidal and also fungicidal and also prevents the reproduction of those organisms, it is now used in various consumer goods ranging from wound dressing products to sportswear," says Niskanen from the Laboratory of Polymer Chemistry at the University of Helsinki, Finland.
While the usefulness of silver has been established, the debate over the toxicity mechanisms of its various forms to microorganisms but also to non-target species continues. Anne Kahru, Head of the Laboratory of Environmental Toxicology at the National Institute of Chemical Physics and Biophysics, Estonia, talks about a whole new field of ecotoxicology: nanoecotoxicology.
So far, little is known about the environmental effects of silver nanoparticles and their toxicity to aquatic organisms. A joint study from the University of Helsinki and the National Institute of Chemical Physics and Biophysics (Tallinn, Estonia), "Toxicity of two types of silver nanoparticles to aquatic crustaceans Daphnia magna and Thamnocephalus platyurus", shows that silver nanoparticles are apparently no more hazardous to aquatic ecosystems than a water-soluble silver salt. The study compared the ecotoxicity of silver nanoparticles and a water-soluble silver salt.
"Our conclusion was that the environmental risks caused by silver nanoparticles are seemingly not higher than those caused by a
|Contact: Jukka Niskanen|
University of Helsinki