Antibacterial activity of conjugated electrolytes

A series of water soluble, cationic, anionic and zwitterionic conjugated polyelectrolytes (CPEs) with main chains based on an arylene ethynylene repeat unit structure with tetraalkylammonium and/or alkylsulfonate side groups were found to exhibit significant antibacterial activity. A number of these complexes also showed pronounced light-induced modulation of their effectiveness, with either biocidal enhancement or suppression, depending on such properties as singlet oxygen sensitization potential and lipophilicity. These collected studies examine the biocidal activity of the CPEs, as determined by Confocal Laser Scanning Microscopy (CLSM) and Flow Cytometry, correlating this activity with the photophysical properties of the polymers. We demonstrate biocidal activity, both in solution and immobilized, of similar ionic conjugated polyelectrolytes. These polymers were tested and shown to be effective in solution, physisorbed or surface grafted on non-porous borosilicate microspheres and grafted on fabrics. Also, studies with templated hollow spheres formed from polymer multilayers show considerable bacterial sequestration and significant biocidal activity, especially upon light exposure. The effective killing of Cobetia marina, Pseudomonas aeruginosa and Bacillus atrophaeus in these systems is also correlated with a requirement for oxygen suggesting that interfacial generation of singlet oxygen is the crucial step in the light-induced biocidal activity. This document begins with an introduction to the problem, including a review of literature. This is followed by an experimental section describing in detail the selection, growth and harvesting parameters for the bacteria and a summary of substrate preparation protocols. A number of biocidal experiments using a variety of compounds and substrates and evaluated with confocal microscopy and flow cytometry are then covered, followed by conclusions and future directions.Defense Threat Reduction Agency (DTRA), contract # W911NF-07-1-0079; Bureau of Indian Affairs for leave time; NSF IGERT CORE Fellowship; Office of Naval Research, AASERT and grant # N00014-05-1-0743Chemistry and Chemical BiologyDoctoralUniversity of New Mexico. Dept. of ChemistryWhitten, David GKeller, David JFulghum, JuliaCabaniss, Stev