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[SANET-MG] buckyballs do bacteria



Nano carbon particles are an important material used in nanotechnology. The paper below is one of a growing number of papers showing that nano-materials may adverse effects on living cells from bacteria to mammals. Unlike biotechnology, nanotechnology is taking the toxic side effects very seriously and making an effort to identify the problems before the products go into wide distribution. Organic certification may have to create a policy on nanomaterials sooner rather than later. Environ. Sci. Technol., ASAP Article 10.1021/es048099n S0013-936X(04)08099-X
Web Release Date: April 28, 2005

C60 in Water: Nanocrystal Formation and Microbial Response (buckyballs)

J. D. Fortner, D. Y. Lyon, C. M. Sayes, A. M. Boyd, J. C. Falkner, E. M. Hotze, L. B. Alemany, Y. J. Tao, W. Guo, K. D. Ausman, V. L. Colvin, and J. B. Hughes*
Abstract:

Upon contact with water, under a variety of conditions, C60 spontaneously forms a stable aggregate with nanoscale dimensions (d = 25-500 nm), termed here "nano-C60". The color, hydrophobicity, and reactivity of individual C60 are substantially altered in this aggregate form. Herein, we provide conclusive lines of evidence demonstrating that in solution these aggregates are crystalline in order and remain as underivatized C60 throughout the formation/stabilization process that can later be chemically reversed. Particle size can be affected by formation parameters such as rates and the pH of the water addition. Once formed, nano-C60 remains stable in solution at or below ionic strengths of 0.05 I for months. In addition to demonstrating aggregate formation and stability over a wide range of conditions, results suggest that prokaryotic exposure to nano-C60 at relatively low concentrations is inhibitory, indicated by lack of growth (0.4 ppm) and decreased aerobic respiration rates (4 ppm). This work demonstrates the fact that the environmental fate, distribution, and biological risk associated with this important class of engineered nanomaterials will require a model that addresses not only the properties of bulk C60 but also that of the aggregate form generated in aqueous media.

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