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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
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*
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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