Abstract: Light Activated Antimicrobial “Roach Motel” Synthesis by Conjugated Polyelectrolyte Deposition (2011 SACNAS National Conference)

Friday, October 28, 2011

Hall 1-2 (San Jose Convention Center)

Taylor Canady , Biomedical Engineering , University of New Mexico, Albuquerque

David Whitten, PhD , University of New Mexico, Albuquerque

Wang Ying , University of New Mexico, Albuquerque

Tom Corbitt, PhD , University of New Mexico, Albuquerque

Kirk Schanze, PhD , Chemistry, University of Florida , Gainesville, FL

Layer-by-layer constructs of conjugated polyelectrolytes which exhibit phenomenal biocidal activity have been synthesized by step-wise adsorption of conjugated polyelectrolytes (CPEs) that contain functionalized ionic groups supported on colloidal particles followed by core dissolution; this biocidal activity can be attributed to the CPE’s photophysical generation of reactive oxygen, and collective morphology of the layer-by-layer microcapsules. Microcapsule “roach motels” were measured against numerous bacterial strains, and carried out using different microcapsule bilayer compositions.

In this study, we have synthesized monodisperse MnCO₃ template particles coated using a layer-by-layer technique of alternating poly(phenylene ethylene)-type conjugated polyelectrolytes followed by dissolution of the inorganic template particles using an ethylenediaminetetraacetate solution. The layer-by-layer deposition of oppositely charged polymers was carried out using several different combinations of CPEs. The CPEs of interest have been shown to generate singlet oxygen upon exposure to visible light and contain pendant quaternary ammonium groups, to enhance biocidal activity. The morphology of the synthesized roach motel is crucial for capture and entrapment of bacteria. Microcapsules have an inherent bright-green florescence emission distinguishing successful deposition of CPEs on the template particle. Studies of the microcapsule in both light and dark environments, roach motel concentration differentials, bilayer counts, and cationic/anionic pair derivatives were carried out against Staphylococcus epidermidis, Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli. Strong biocidal activity of the polyelectrolyte capsules were verified through confocal fluorescence microscopy and bacterial viability was distinguished by basic staining procedures. Flow cytometry data was collected to provide a quantitative measure and accurate characterization of live/dead bacteria populations.