A newly published study by researchers at the University of Southern Denmark has demonstrated that nano-silver particles are able to enter human cells, producing potentially harmful free radicals and changes in certain cell proteins.
The researchers, led by Associate Professor Frank Kjeldsen and Dr Thiago Verano-Brava, looked at the effect of two sizes (100nm and 20 nm) of nano-silver particle on human intestinal cells grown in culture in the laboratory. They used a variety of techniques to examine interactions between the particles and proteins in the cells.
The results showed that while both sizes of particle produced a response, only the smaller particles were able to enter the cells and cause direct effects. These included the production of reactive oxygen species and carbonylation of proteins, as well as stimulating the production of certain proteins.
“We can confirm that nano-silver leads to the formation of harmful, so called free radicals in cells. We can also see that that there are changes in the form and amount of proteins. This worries us,” say Kjeldsen and Verano-Brava.
Nano-silver is used as an antimicrobial component in certain types of food packaging and is also sold as a dietary supplement in some markets. The Danish Veterinary and Food Administration has reportedly responded to the research by warning against taking these supplements, which are available to buy on the Internet.
The study is published in the journal ACS Nano and an abstract can be found here.