The Naval Research Laboratory's self-decontaminating fabric technology uses enzymes to break down chemical toxins on contact without leaving harmful residues.
By Janet Bealer Rodie, Associate Editor
echnology designed to protect military personnel from exposure to toxic chemical agents
now is available for licensing for civilian uses. A cost-effective, ultrathin, self-decontaminating
composite coating for fabrics and other materials — developed at the Washington-based US Naval
Research Laboratory’s (NRL’s) Center for Bio/Molecular Science and Engineering (CBMSE) — contains
enzymes that actively and rapidly break down and neutralize pesticides such as methyl parathion
(MPT) and other toxic chemicals on contact without producing harmful residues.
The technology involves noncovalent incorporation of organophosphorous hydrolase (OPH) and organophosphoric acid anhydrolase (OPAA) enzymes within a polyelectrolyte film. A stabilizing, abrasion-resistant organosiloxane polymeric amphiphile capping layer protects the enzymes from degradation by external stresses and attracts toxins to the fabric surface. Alok Singh, Ph.D., principal investigator at the CBMSE, said OPH and OPAA are effective against most chemical agents and pesticides. He added that the coating may be customized by adding additional layers of enzymes that work against specific toxins. A “cocktail of enzymes,” as he calls it, would render the coating even more multifunctional than the basic coating.
The coating may be applied to cotton, glass cloth, paper and man-made materials, according to co-investigator, Walter Dressick, Ph.D. Coating methods include dip coating, spin coating or spraying. Singh said dip coating is the most cost-effective of the three methods and also enables the best control of contact between the coating bath and the material to be coated.
Coating is applied to cotton thread (upper left), which is knitted into a fabric upper
right). Contact with methyl parathion (MPT) turns the fabric yellow bottom), indicating MPT
Possible applications for the coating include protective clothing, water purification filters and decontamination wipes used in connection with homeland security, agricultural and other activities.
When applied to cotton thread prior to weaving or knitting, the coating provides a thorough
treatment of the resulting fabric, which continues to perform as intended after repeated washing
under certain conditions. Also, because the coating is active throughout the fabric, that fabric
should provide better protection, including in seamed areas, than do conventional composite fabrics
that contain rubber or man-made impermeable materials, or highly adsorbent materials such as active
The NRL notes that protective garments made with these cotton fabrics are lighter in weight and more comfortable than those made with conventional composites — which tend to be bulky, heavy and uncomfortable; and some of which may be used only once. And, the enzymes in the coating eliminate the danger of off-gassing and creation of a more dangerous chemical — as might occur when charcoal decomposes — as well as any special disposal needs, because those enzymes break down chemical agents without themselves degrading.
Singh said the coating has generated interest in the commercial arena. He also is conducting research to develop antimicrobial applications for the technology.
For more information about the NRL’s coating technology, contact Jane F. Kuhl, Technology Transfer Office (202) 767-3083, email@example.com .