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 support 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-butyl phosphate.
A series of comparison tests took place to confirm the effectiveness of seven different anthrax decontamination technologies for commercial purposes. Several agencies and government departments were involved in this through sponsorship and the testing was carried out by the Biological Weapons Improved Response Program. They all agreed to put to test the technologies including the Michigan nanoemulsion, the Sandia foam, metal oxide nanoparticles, ozone and other products based on surfactants. The tests showed some more than amazing results such as the ability of the nanoemulsion to reduce the activity of all sorts of spores in test samples by 90 % within just a few hours. They also decided to test different surfaces such as noninfectious anthrax resembling bacterium, a carpet contaminated with B. globigii which is a known anthrax simulant, painted wallboard, cement and ceiling tiles. Unfortunately, none of the products showed the ability to completely and totally decontaminate all surfaces but the Michigan and Sandia formulations proved to be extremely efficient when it comes to decontamination. It will still take a lot of research work to realize the full potential of such formulations but there is a lot of hope that the results will be more than positive and useful.