Light-Induced Biocidal Action of Conjugated Polyelectrolytes Supported on Colloids

• Published in: Langmuir Vol. 24; no. 19; pp. 11053 - 11062
• Main Authors: Chemburu, Sireesha, Corbitt, Thomas S, Ista, Linnea K, Ji, Eunkyung, Fulghum, Julia, Lopez, Gabriel P, Ogawa, Katsu, Schanze, Kirk S, Whitten, David G
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 07.10.2008
• Subjects: Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - pharmacology; Biological Interfaces: Biocolloids, Biomolecular and Biomimetic Materials; Chemistry; Colloidal state and disperse state; Colloids; Electrolytes; Exact sciences and technology; General and physical chemistry; Light; Microscopy, Electron, Scanning; Molecular Structure; Oceanospirillaceae - drug effects; Photochemistry; Physical and chemical studies. Granulometry. Electrokinetic phenomena; Polymers - chemistry; Polymers - pharmacology; Pseudomonas aeruginosa; Pseudomonas aeruginosa - drug effects; Singlet Oxygen - chemistry; Surface physical chemistry; Water; Polyelectrolyte; Triplet state; Binary compound; Oxygen; Support; Polymer; Structure; Silica; Colloid; Diameter; Colloid particle
• ISSN: 0743-7463; 1520-5827
• DOI: 10.1021/la8016547

A series of water soluble, cationic conjugated polyelectrolytes (CPEs) with backbones based on a poly(phenylene ethynylene) repeat unit structure and tetraakylammonium side groups exhibit a profound light-induced biocidal effect. The present study examines the biocidal activity of the CPEs, correlating this activity with the photophysical properties of the polymers. The photophysical properties of the CPEs are studied in solution, and the results demonstrate that direct excitation produces a triplet excited-state in moderate yield, and the triplet is shown to be effective at sensitizing the production of singlet oxygen. Using the polymers in a format where they are physisorbed or covalently grafted to the surface of colloidal silica particles (5 and 30 μm diameter), we demonstrate that they exhibit light-activated biocidal activity, effectively killing Cobetia marina and Pseudomonas aeruginosa. The light-induced biocidal activity 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.