While we have all seen the news stories about the various toxic gases being used to decontaminate government buildings of anthrax, I feel it is worthwhile to remind everyone that surfactants can also serve well in this role. After all, soaps and detergents play a ‘decontamination’ role for all of us every day, as we wash our hands and clothes, killing bacteria and other harmful germs!
The following excerpt can be found in an issue of Chemical & Engineering News (November 26, 2001), in the article “Ousting Anthrax” by Stephen Ritter, highlighting the use of foam and emulsion surfactant formulations for anthrax decontamination.
…there are a handful of commercially available inexpensive liquid decontamination products that can neutralize chemical agents and/or kill most microbes within a few minutes of exposure. One of the best known of these is a foam invented at Sandia National Laboratories by chemists Mark D. Tucker and Maher E. Tadros.
The nontoxic, noncorrosive Sandia foam, developed in the late 1990s, is a combination of a surfactant and water-soluble polymers that supports proprietary nucleophilic reagents and mild oxidizing reagents, such as hydrogen peroxide. It already has been proven to be very effective against anthrax spores. The researchers believe the foam’s surfactant damages the spores’ protective protein membrane, specifically breaking phosphate and sulfide bonds, which allows the oxidizing agent to attack DNA inside the spores.
Sandia licensed rights to commercialize the foam last year to Modec Inc. of Denver, and EnviroFoam Technologies, Huntsville, Ala. The companies’ products can be applied as a foam, spray, mist, or fog and generally are limited to use on flat surfaces such as hardwood floors, walls, and furniture. Once bacteria are neutralized, the residual liquid can be wiped or vacuumed away.
A similar method that has good activity against anthrax spores is a water-in-oil nanoemulsion described in testimony by hearing witness James R. Baker Jr., a professor of internal medicine and director of the Center for Biologic Nanotechnology at the University of Michigan. The nanoemulsion developed by Baker and his students & coworkers in work funded by the Department of Defense is made from water, soybean oil, Triton X-100 surfactant, and tri-n-butylphosphate.
It has droplet sizes of about 200 to 400 nm in diameter that fuse with spores and subsequently disrupt the protein membrane, Baker explained. The nanoemulsion has been shown to inactivate more than 90% of spores in test samples within four hours. The material has the consistency of a hand cream and can be used topically, or it can be diluted with water and used as a spray. The nanoemulsion is being commercialized by NanoBio Corp., Ann Arbor, Mich., a company Baker started to develop the technology.
The effectiveness of seven commercial anthrax decontamination technologies was checked in a series of comparison tests carried out this year by the Biological Weapons Improved Response Program, which is sponsored by several government departments and agencies. The technologies tested include ozone, metal oxide nanoparticles, the Sandia foam, the Michigan nanoemulsion, and other surfactant-based products.
Tests were carried out on six different surfaces such as ceiling tiles, cement, painted wallboard, and carpet using the anthrax simulant B. globigii, a noninfectious bacterium that closely resembles anthrax. The Sandia and Michigan formulations came out as the top two clear winners, although none of the products was able to completely decontaminate all surfaces in the test.