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Can Asbestos Help Us Understand Nanotoxicity?

Posted by ScuttleMonkey on from the don't-put-them-in-there-put-them-in-there dept.

Roland Piquepaille writes "Occupational Hazards is running an interesting article about how using our knowledge of asbestos could help us to assess the risks from nanoparticles, or their nanotoxicity. Today, it's unknown if nanomaterials under development are dangerous to human beings or to our environment. Some people think that nanoparticles can move to our lungs or our brains, presenting a significant threat to our health. Other scientists think there is no danger because we have been exposed to nanoparticles for thousands of years, such as ashes from volcanic eruptions. For example, nanotubes which are now used for many industrial developments, have similar shapes as fibers like asbestos, being long and extremely thin. And like nanomaterials today, asbestos was considered as harmless when humans were exposed to it. While the comparison has some merit, more research needs to be done before drawing any conclusion."

5 of 127 comments (clear)

  1. Asbestos? by geomon · · Score: 4, Informative

    I'm not sure if asbestos is an appropriate analog for nano-based respiratory hazards. When Dr. Irving J. Seilkoff published his report on the link between asbestos and respiratory ailments, there was already an abundant record of impairment in the form of asbestosis. Asbestosis is a scarring and sedimentation of the lung due to particulate inhalation. It is in a general family of respiratory ailments known as pneumoconiosis. That group includes silicosis (affects quarry workers) and black lung (coal miners). The link that Seilkoff is credited with is the connection of asbestos to lung cancer, which is has only one known asbestiform species in direct connection: crocidolite. This blue amphibole was used in ship construction and in homes in and around Australia (sorry mates!). This asbestiform mineral has been directly connected to one of the most virulent forms of lung cancer, mesothelioma. This cancer of the plural lining is fatal within months of diagnosis.

    Connections between other asbestiform minerals and cancer is more complex. Tremolite and serpentenite have also been linked to lung cancer, but the connection is much more tenuous. Another factor that would complicate the study of asbestos as an analog is the size: an asbestos fiber is counted for toxicological purposes only when it fits a 5:1 aspect ratio and is >5 micron in length. That is the geometry that is most likely to fit into the alveoli. This deep penetration of asbestos into the tissues of the lung is presumed to be the mechanism that leads to cancer. Plaques form around the embedded spines of asbestos as microphages attack and envelope the fibers. This process leads to a general lessening of the effective surface area for gas transfer leading to shortness of breath. The mechanics leading to cancer, however, are dubious and have plagued researchers for more than two decades.

    I can't see how the study of asbestos can illuminate any area of occupational health. I can, however, see how injury claims attorneys would use the experience of asbestos litigation in any future attack on the nano-industry.

    --
    "Rocky Rococo, at your cervix!"
  2. Re:Health risk like Asbestos? by Rosco+P.+Coltrane · · Score: 3, Informative

    why asbestos causes harm. Is the the morphology (shape) of it that is the key?

    A doc friend of mine told me asbestos particles are long and pointy and act as minute glass shards inside the lung alveoles, and they pierce cells over and over as the lungs open and collapse during respiration. Cells repair themselves all the time, but under these repeated micro-stresses, they have to do it a whole lot more, and eventually fail to do it correctly and turn into cancer cells.

    --
    "A door is what a dog is perpetually on the wrong side of" - Ogden Nash
  3. We know how to make non-toxic buckyballs by vik · · Score: 5, Informative

    That study is somewhat old hat. Have a look here and you'll see that the mechanism is now understood.

    In short, you can make toxic, or non-toxic buckyballs. The more bits you dangle on the outside of the buckyballs, the less toxic they become. Nanomachine designers will be aware of this and act accordingly.

    Vik :v)

    1. Re:We know how to make non-toxic buckyballs by TheMohel · · Score: 3, Informative

      Not to nit-pick too much, but from that study we now know how to make non-cytotoxic buckyballs, or at least how to control their cytotoxicity. The test was just cell culture driven, and suggested that modifications to the buckyballs reduced their general cytotoxicity in culture. A mechanism (free radical generation by the buckyball) was suggested but has not been proven.

      The article stated, and I heartily endorse the statement, that this is not a full toxicologic risk assessment, but simply a first step.

      Having said that, however, that first step was a big one and an important one.

  4. Re:Health risk like Asbestos? by Anonymous Coward · · Score: 3, Informative

    It's not just the poking of holes in cells. Membranes self heal pretty well. The other thing to take into account is that macrophages try to distroy the foreign matter by releasing chemicals like hydrogen peroxide. Those damaging chemicals can get into the normal cells via the holes punched in the membranes and damage the DNA inside, which could lead to cancer.