| AVS 54th International Symposium | |
| Biomaterial Interfaces | Tuesday Sessions |
| Session BI-TuP |
| Session: | Biomaterials Interfaces Poster Session |
| Presenter: | R.A. Brizzolara, NSWC, Carderock Division |
| Authors: | R.A. Brizzolara, NSWC, Carderock Division J.H. Wynne, Naval Research Laboratory J. Jones-Meehan, Department of Homeland Security |
| Correspondent: | Click to Email |
The goal of this work is to develop a surface that demonstrates biocidal activity with less than 0.5% biocide concentration in the bulk material. The incorporation of an amphiphilic biocide as a surface-active component in a resin matrix is being investigated as a means of achieving a higher biocide concentration at the surface (and therefore better biocidal efficacy), while maintaining low bulk biocide concentrations. The amphiphilic quaternary ammonium compounds containing both aliphatic and oxyethylene moieties afforded greatest biocidal activity. These molecules were synthesized via simple condensation of a tertiary dimethyl-N-alkylamine with the corresponding halo-oxyethylene. Purity was confirmed using 1H- and 13C-NMR. The biocide-containing urethane coating was dried on glass slides for microbiological analysis and on gold surfaces for x-ray photoelectron spectroscopy (XPS) analysis. Microbiological analysis was performed to determine biocidal efficacy of coating formulations against S. aureus (Gram-positive bacterium). 10 µL of bacterial culture was placed on the surface of the slide. After 2 hours, the slide surface was swabbed. Swab contents were resuspended in appropriate neutralization media, serial dilution was performed with plating on LB agar plates. XPS was used to determine the quantity of biocide at the coating surface compared to the bulk to determine the segregation of biocide to surface, and to correlate surface concentration of biocide to the coating’s biocidal efficacy. The N1s binding energy shift between nitrogen in quaternary ammonium and nitrogen in polyurethane was used to differentiate biocide from polyurethane. The XPS analysis demonstrated surface enrichment of two quaternary ammonium-based biocides in a polyurethane coating by approximately a factor of 10 compared to the bulk. The quaternary ammonium-containing materials exhibited increased killing of - S. aureus cells compared to the control (polyurethane containing no biocide). These results indicate that the use of surface-active biocides can result in significant biocidal efficacy with small bulk biocide concentrations. This work was sponsored by the DARPA Defense Sciences Office.