The increasing use of nanomaterials in a wide variety of applications has led to several studies on their environmental and toxicological impact, which have raised concerns about their potentially hazardous nature to humans.1 For example, it has been shown that carbon nanotubes can accumulate in the lungs of rats2,3 and that buckminsterfullerenes (C60) can bind to and deform DNA sequences.4 A novel class of inorganic/organic hybrid nanomaterials are polyhedral oligomeric silsesquioxanes (POSS). The size, geometry and ease with which the molecules can be functionalized cause POSS to be used in a wide variety of applications as nanoscale building blocks. However, little is known about their environmental and physiological impact. Here we present results for the calculation of the octanol-water partition coefficient (Kow), a quantity commonly used to gauge the accumulation of a substance in an organic phase, such as sediment or tissue. The KOW has been determined through molecular dynamics simulation for several POSS molecules. In particular, the effect of an alkyl tether group on the solubility of the POSS molecules has been determined.
References
1. Holsapple, Michael P., William H. Farland, Timothy D. Landry, Nancy A. Monteiro-Riviere, Janet M. Carter, Nigel J. Walker, and Karluss V. Thomas. "Research Strategies for Safety Evaluation of Nanomaterials, Part II: Toxicological and Safety Evaluation of Nanomaterials, Current Challenges and Data Needs," Toxicological Sciences, 88(1), 12-17, (2005).
2. Service R. F., "American Chemical Society meeting: Nanomaterials show signs of toxicity," Science, 300, 243-243 (2003).
3. Warheit D. B., Laurence B. R., Reed K. L., Roach D. H., Reynolds G. A. M. and Webb T. R., "Comparative pulmonary toxicity assessment of single-wall carbon nanotubes in rats," Toxicol. Sci., 77, 117-125 (2004).
4. Zhao X.C., Striolo A., Cummings P.T. "C-60 binds to and deforms nucleotides." Biophysical Journal 89, 3856-3862, (2005).