AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Inactivation of Bacteria by Nanotechnology-Based Consumer Spray Products
JENNIFER THERKORN, Leonardo Calderón, Benton Cartledge, Brian Majestic, Gediminas Mainelis, Rutgers, The State University of New Jersey
Abstract Number: 409 Working Group: Bioaerosols
Abstract Nanoparticles are being increasingly incorporated into everyday consumer spray products, like household cleaners and cosmetics. The impacts of these aerosolized nanomaterials on the bacteria to which we are exposed are currently unknown. This research investigates bacterial inactivation caused by consumer nanospray products. Six commercially available Ag-based nanospray products, including cosmetic and antifungal sprays, were investigated. Minimal inhibitory concentration (MIC) tests were performed using agar plate dilution method for two bacteria commonly used for hardy vs. sensitive species in bioaerosol studies (Escherichia coli and Bacillus atrophaeus). Some nanoproducts with advertised antimicrobial properties were found to be ineffectual while other nanoproducts inhibited microbial growth with MIC’s ranging from 40,000 to 160,000 ppm. Nanoproducts and controls were aerosolized using 3-jet Collison nebulizer and released particles were sampled out of a chamber using an Andersen six-stage cascade impactor onto spread-plated bacterial films of E. coli and B. atrophaeus. Controls included 20 nm and 1 micrometer inert polystyrene latex particles in ethanol to mimic impaction stress of agglomerated nanoproduct particles. By observing inactivation spots in bacterial films post plate incubation, one deodorizing product and one lime scale removing product caused inactivation on impactor stages for particles > 2.1 micrometer. As inactivation was not seen for controls nor other nanoproducts sampled with higher mass than the inactivating products, inactivation appeared to be nanoproduct-specific. ICPMS explored metals present in these nanoproducts and single-particle-ICPMS explored the size distribution of nanosilver once aerosolized. Inactivating products typically had lower total silver concentration compared to ineffectual products. However, as determined by single-particle-ICPMS, inactivating nanoproducts had smaller mean diameter of silver particles (20 – 30 nm) vs. ineffectual nanoproducts (40 – 50 nm). The relationships between liquid and aerosol phase particle size and nanoparticle inactivation efficacy requires further investigation. Future tests will investigate inactivation of bacteria by nanospray particles in airborne phase.