Assaying Benefits of Poly[styrene-4-(trimethylammonium)methyl Triiodide] in Respiratory Protection Devices
Final rept. 1 Feb 2007-30 Nov 2009
APPLIED RESEARCH ASSOCIATES INC TYNDALL AFB FL
Pagination or Media Count:
By analogy to the accepted mechanism for disinfection by iodine in water, a mechanism was earlier proposed to rationalize in-vitro disinfection of bioaerosols after passage through air filter media coated with polystyrene-4-trimethylammoniummethyl triiodide PSTI that invoked near-collision transfer of I2 from PSTI onto the negatively charged surface of passing particles. This report describes progress toward two experiments designed to test and refine that model and to evaluate the increment to respiratory protection available by adding PSTI to inert mechanical air filter media. The controlled aerosol test system CATS was designed and built to deliver a constant - 10 challenge of aerosolized respiratory pathogens through samples of air filter media to groups of 5 mice. By varying the challenge concentration and comparing rates of infection in groups behind mechanically equivalent control and PSTI-containing media we expect to measure the effective decrease in penetrating infectivity. The second experiment was accomplished in 20-L bags assembled from commercial food wrapping material, which were filled with a bioaerosol of MS2 coli phage that had been passed through an inert or PSTI-containing air filter medium. After 15 or 30 minutes incubation the contents of the bag were drawn through an impinger containing dilute thiosulfate solution and plated to determine viable counts. Data noise in the control experiment prevented drawing a firm conclusion but loss of viability in the aerosol phase appeared faster in the treated group at high humidity, suggesting that water is necessary to the antimicrobial action and that PSTI might be more effective in collective than individual protection applications.
- Chemical, Biological and Radiological Warfare