Researchers are continuing to investigate how the shape and size of carbon nanotubes (CNT) affect the pulmonary systems of mice over time.  To answer the question, researchers are depositing CNT of varying sizes, length, and thickness into the lungs of mice and assessing the cellular interactions at varying intervals.  Several recent papers have been published suggesting that the scientific community is progressing toward some answers.
Continue Reading The Shape and Size of Carbon Nanotubes Impact the Potential Biological Response

Are carbon nanotubes helping to cause cancer, cure cancer, both, or neither?  Several years ago, carbon nanotubes shot to mainstream consciousness in large part due to concerns that they may present health risks similar to asbestos fibers.  A 2010 study published in The Journal of Toxicology and Environmental Health found that carbon nanotubes can induce apoptosis, DNA damage, and initiate biological responses.  In 2010, and again in 2013, the National Institute for Occupational Safety and Health (NIOSH) issued a Current Intelligence Bulletin recommending exposure limits for carbon nanotubes and carbon nanofibers based on the concerns over possible adverse health effects.   A 2013 study, however, suggested that concerns about the similarities of bio-reactivity and pathogenicity between asbestos fibers and carbon nanotubes may be alleviated through modification of length and chemical modification of the nanotube surface.
Continue Reading Carbon Nanotubes and Cancer: Potential Cause or Cure?

Late last month the National Institute for Occupational Safety and Health (NIOSH) issued Current Intelligence Bulletin 65 recommending exposure limits for carbon nanotubes (CNTs) and carbon nanofibers (CNFs) based on the concerns over possible adverse health effects.

Citing research studies that demonstrated adverse lung effects on rodents at relatively low-mass doses of CNTs and CNFs, including pulmonary inflammation and rapidly developing fibrosis, NIOSH stated that worker exposure needs to be minimized.

NIOSH proposed a recommended exposure limit (REL) of µg/m3 of elemental carbon as a respirable mass 8-hour time-weighted average.  NIOSH noted, however, that because of some residual risk at the REL and uncertainty concerning chronic health effects and possibly carcinogenicity, efforts should be made to reduce exposures as much as possible.
Continue Reading NIOSH Proposes Exposure Limits for Carbon Nanotubes and Carbon Nanofibers