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Volume 87 Issue 33 | p. 37 | Concentrates
Issue Date: August 17, 2009

Nanomaterials Bug Fruit Flies

Carbon nanomaterials don't seem to harm larvae, but glom onto adults and impair their mobility, leading to early mortality
Department: Science & Technology | Collection: Critter Chemistry
News Channels: Environmental SCENE
Keywords: carbon nanoparticles, environment, fruit flies
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Adult fruit flies exposed to dry powders of carbon nanomaterials: At top, an adult fly before and after exposure to single-walled carbon nanotubes (SWNTs), which coat the fly's entire body. In the SEM images starting in the second row, a fly's compound eye before exposure, after SWNT exposure, and after carbon black exposure. In the third row, a fly's wing before exposure, after exposure to crushed C60, and after exposure to carbon black. On the bottom row, an adult fruit fly's leg and foot before and after exposure to multiwalled carbon nanotube spherical aggregates, which decorate the pincer structure used for gripping.
Credit: Environ. Sci. Technol.
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Adult fruit flies exposed to dry powders of carbon nanomaterials: At top, an adult fly before and after exposure to single-walled carbon nanotubes (SWNTs), which coat the fly's entire body. In the SEM images starting in the second row, a fly's compound eye before exposure, after SWNT exposure, and after carbon black exposure. In the third row, a fly's wing before exposure, after exposure to crushed C60, and after exposure to carbon black. On the bottom row, an adult fruit fly's leg and foot before and after exposure to multiwalled carbon nanotube spherical aggregates, which decorate the pincer structure used for gripping.
Credit: Environ. Sci. Technol.

Carbon nanomaterials hold great promise for applications ranging from electronics to medicine. But their environmental impact is still being determined, with most toxicological studies conducted so far on cultured cells rather than on intact organisms. That’s why Xinyuan Liu, Robert H. Hurt, David M. Rand, and coworkers of Brown University studied the effects of carbon nanomaterial exposure on fruit fly larvae and adults (Environ. Sci. Technol., DOI: 10.1021/es901079z). The researchers found that when larvae ingested various types of carbon nanomaterials, there was, surprisingly, no impact on development or survival, although some nanomaterials accumulated in tissues. In contrast, exposing adult flies to dry powders of some carbon nanomaterials impaired their mobility and caused them to die within hours. Nanomaterials that form small aggregates, such as carbon black and single-walled nanotubes, were more toxic to the flies than nanomaterials with larger aggregate sizes, they noted, probably because the small aggregates strongly adhere to the flies’ eyes, legs, wings, and breathing holes. In a test-tube assay, flies were observed spreading attached nanomaterials to uncontaminated flies while grooming themselves, which suggests that insects could transport carbon nanomaterials from manufacturing or waste sites.

Brown University researchers measured the time required for fruit flies to climb up a glass test tube after exposure to (from left) no nanomaterial (control), fullerenes (C60), toluene-washed C60 (W C60), carbon black (FDA-CB), toluene-washed carbon black (W FDA-CB), single-walled nanotubes (APSWNT), toluene-washed single-walled nanotubes (W APSWNT), multiwalled nanotube arrays (APMWNT), or toluene-washed multiwalled nanotube arrays (W APMWNT). Materials that adhered most to the fruit flies significantly impaired the insects' mobility.
Credit: David Rand/Brown University
 
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