A new method has been developed by a research team at the National Institute of Standards and Technology (NIST) to influence the behavior of metal-based nanoparticles using mild electric current to enable scientists to study the hazardous effects of nanoparticles on cell cultures.
The method involves capturing nanoparticles on a surface and then releasing them from the surface whenever required. The method is advantageous as it collects the nanoparticles in a layer with one particle thickness and enables them to be dispersed uniformly into a fluid sample to decrease clumping. Clumping is a frequent problem that can mask the characteristics of nanoparticles during their reactions with living tissue. Darwin Reyes, who serves as physicist at NIST, stated that these benefits of the new method make them suitable for toxicology studies.
The NIST method allows controlled release of nanoparticles into a fluid stream that passes over a group of cells enabling researchers to study the responses of cells over time, or whether the responses of the living cells varies with changes in the concentration of the nanoparticles.
For this method, the research team utilized a gold surface coated with positively charged, long molecules. The nanoparticles used are made from gold and are coated with slightly negatively charged citrate molecules. The negative charge of the citrate molecules attracts the nanoparticles to the surface and by applying a mild electric current the attraction is broken. Reyes stated that since the surface coating is designed to attract various materials, different types of nanoparticles can be drawn and released by this method.