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NIST Creates Novel Method for Testing Nano Toxicity

by Editor1 last modified June 19, 2011 - 12:35

A team at the National Institute of Standards and Technology (NIST) has developed a novel way to help researchers better determine health risks from nanoparticles and conduct more accurate toxicological studies on human tissues.

NIST Creates Novel Method for Testing Nano Toxicity

NIST’s testing allows scientists to more accurately assess nano toxicity and other health hazards.

The NIST team created a method of attracting and capturing metal-based nanoparticles on a surface -- and then releasing them at the desired moment. The method, which uses a mild electric current to influence the particles' behavior, could allow scientists to expose cell cultures to nanoparticles so that any lurking hazards they might cause to living cells can be assessed effectively.

Another advantage to the approach, NIST researchers said, is that it can collect nanoparticles in a layer as small as one-particle thick. This allows particles to be evenly dispersed into a fluid sample, which eliminates the common problems of “clumping” particles, according to NIST physicist Darwin Reyes.

"Many other methods of trapping require that you modify the surface of the nanoparticles in some way so that you can control them more easily," Reyes said in a statement. "We take nanoparticles as they are, so that you can explore what you've actually got. Using this method, you can release them into a cell culture and watch how the cells react, which can give you a better idea of how cells in the body will respond."

Other existing means of studying nanoparticle toxicity do not enable precise delivery of particles to cells. The NIST method allows nanoparticles to be released in a controlled fashion into a fluid stream that flows over a colony of cells, mimicking the way such particles would encounter cells inside the body.

The method uses a gold surface covered by long, positively charged molecules. The nanoparticles, also made of gold, are coated with citrate molecules that have a slight negative charge. The charge draws them to the surface covering, and the attraction can be broken using only a slight electric current. Because the surface covering can be designed to attract different materials, a variety of nanoparticles could be captured and released with the technique, Reyes added.

The work appears in the May 20011 edition of Applied Surface Science.