Contaminants in nanoparticles affect cells

摘要

Nanoparticles and other nanoscale materials are used as imaging labels, as drug-delivery vehicles, and in lab-on-a-chip devices. But, as Helen Vallhov and colleagues at the Karolinska Institute, Stockholm University, and the Royal Institute of Technology (all in Sweden) have demonstrated, close attention needs to be paid to how the materials are synthesized. The investigators found that contaminants carried over from the production of gold nanoparticles caused certain cells to prematurely change their characteristics. Vallhov and colleagues studied how dendritic cells, which play an important role in immune responses as they mature, reacted to 7-nm spherical gold nanoparticles. When exposed to the nanoparticles, the cells matured within 24 h, which was earlier than normal. The way in which the cells matured seemed to indicate that they were reacting to the presence of an endotoxin. Endotoxins are typically found in the outer membrane of Gram-negative bacteria and are often made from lipopolysaccharides (LPSs). Because LPSs are found throughout our normal surroundings, they can be introduced through water, chemicals, or equipment. Vallhov and colleagues measured LPS concentrations of 12-51 ng/mL in their nanoparticle samples.