by Dr. Barbara Price
The promise and threat of nanotechnology
Nanoparticles are those under 100 nm in size. These can be made of a variety of materials including carbon nanotubes, fullerenes (carbon based bucky balls), and even metal oxides. Due to their size, nanoparticles behave differently than macro- and micro-particles, chemically and physically. Nanotechnology is here and developers of products such as labs-on-chips, sensors, computer networks, solar materials, cosmetics, sunscreens, paints, pharmaceutical companies, etc. are pressing ahead, with some cognizance of potential dangers.
Toxicity issues of the actual nanomaterials have been questioned, but since one of the uses is to encapsulate drugs (and other materials) so that they can be delivered either more directly or more easily to disease targets in the body, toxicity goes beyond that of the actual nanomaterial.
University of Michigan Medical School scientists reported the first steps for a nasal nanoemulsion-based vaccine for anthrax in this month's issue of Infection and Immunity. [Infect Immun. 2007 Aug;75(8):4020-9.] The emulsion was based on soybean oil, alcohols and surfactants and encapsulated a recombinant protein from B. anthracis. This combination induced a systemic and cellular immunity into the test animals and also a more localized immunity within the nasal and lung mucous membranes.
The method of the vaccine promises greater stability (no refrigeration), lower costs (just enough for the targeted tissues), and easier vaccine delivery. But the article also highlights the evolving concerns in dual use, especially in CB defense.
Nanotechnology encapsulated drugs are nanotechnology encapsulated chemical delivery systems. Can that same technology be used to deliver a nerve agent? Will chemicals that are not considered highly toxic actually be more toxic because nanotechnology deliveries avoid some of our "natural" defenses, such as our skin and mucous membranes?
Mustard may raise blisters upon skin contact, but imagine if it is encapsulated and able to readily pass through the skin. How will mustard act? Which chemicals will be delivered directly to the bloodstream? How small a dose will be toxic? How cheap will these agents be? Will the delivery systems and properties change? How can we control this immoral use, while still developing better therapeutics? The technology is not evil or immoral, but the uses can be.
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