IN A NUTSHELL: Antimicrobial N-halamine polymer coatings composed of alternating monolayers of cationic polyamines and anionic polycarboxylates assembled by the layer-by-layer method. Interlayer crosslinks are provided by amide bonds between polymer chains formed by heating or treatment with amidation reagents. The crosslinks provide physical and chemical durability, as well as the source for the active N-halamine chemistry. N-H bonds are converted to N-Cl bonds through treatment with hypochlorite (bleach). Optimum activity is achieved at thickness of about 50 nm [5 alternating bilayers of polyallylamine hydrochloride (PAH) and polyacrylic acid (PAA)].

BENEFITS: Conveys strong antimicrobial properties to coated articles, which can be fabrics or hard surfaces. Polyelectrolytecomponents are inexpensive, widely available, nontoxic, and easy to handle. They can be coated onto surfaces through sequentially immersion, spin coating, spray coating, or wiping on. The process of immersion is easy to automate, and allows the uniform coverage of objects with complex three dimensional shapes. Crosslinking is achieved either through heating above 100° C to form amide interchain crosslinks, or alternatively, by treatment with an amidation reagent, such as DCC or EDC. N-halamines are a potent and highly stable source of biocidal chlorine for on-demand delivery. After the chlorine content has been depleted from the coating, it can be regenerated repeatedly by further treatment with bleach.

STAGE OF DEVELOPMENT: Proof of principle in vitro experiments demonstrated Log 2.6 (99%) reduction of Sterne strain B. anthracis spores after 24 exposure to coated surfaces. Optimum results to date achieved for crosslinked, chlorinated 5 bilayer coating (~50 nm) with carboxylate groups located at the surface.

NEXT STEPS: New SBIR program has been funded to optimize coating parameters, and to test against E. coli, MRSA, and C. difficile. Coating durability and lifetime will also be probed. Seeking agreement to manufacture for or license to a company with significant antimicrobial coating portfolio and market penetration.