Nanoparticle Safety
“Nanoparticles present possible dangers, both medically and environmentally. Most of these are due to the high surface to volume ratio, which can make the particles very reactive or catalytic. They are also able to pass through cell membranes in organisms, and their interactions with biological systems are relatively unknown. A recent study looking at the effects of ZnO nanoparticles on human immune cells has found varying levels of susceptibility to cytotoxicity. Smaller nanoparticles evinced increased cytotoxicity. Lymphocytes (especially naive T cells) were found to be more resistant to nanoparticle cytotoxicity than monocytes, likely due to the capacity of the latter to produce higher levels of reactive oxygen species in response to internalized nanoparticles. Previously activated memory T cells were more susceptible than naive T cells, implying a relationship between cell-cycle and nanoparticle susceptibility. In addition, nanoparticle concentrations below those causing appreciable cell death nonetheless induced the production of proinflammatory cytokines, such as IFN-γ and TNF. Despite these laboratory findings, free nanoparticles in the environment may rapidly agglomerate and thus leave the nano-regime. Nature itself presents many nanoparticles to which organisms on earth may have evolved immunity (such as salt particulates from ocean aerosols, terpenes from plants, or dust from volcanic eruptions).”
“According to the San Francisco Chronicle, "Animal studies have shown that some nanoparticles can penetrate cells and tissues, move through the body and brain and cause biochemical damage they also have shown to cause a risk factor in men for testicular cancer. But whether cosmetics and sunscreens containing nanomaterials pose health risks remains largely unknown, pending completion of long-range studies recently begun by the FDA and other agencies." Diesel nanoparticles have been found to damage the cardiovascular system in a mouse model.”
Recent Journal Articles
Evaluation of Cyto- and Genotoxicity of Poly(lactide-co-glycolide) Nanoparticles
(196-202) Journal of Polymers and the Environment 19 #1 (2011)
De Lima et al , Brazil usingcellular viability assays using fibroblast cells showed no significant alterations compared with the negative control. A cytogenetic analysis of human lymphocyte cells showed no significant changes in the mitotic index in relation to the control, indicating that in the concentration range tested, the particles used in the experimental models did not present cyto- or genotoxicity. For the tests conducted in this work we can conclude that biodegradable and biocompatible PLGA nanospheres are not toxic in the cell cultures tested (fibroblast and lymphocyte cells) and in the range of concentrations employed. (RDC 4/22/2011)