Light and Dark-Activated Biocidal Activity of Conjugated Polyelectrolytes

• Published in: ACS applied materials & interfaces Vol. 3; no. 8; pp. 2820 - 2829
• Main Authors: Ji, Eunkyung, Corbitt, Thomas S, Parthasarathy, Anand, Schanze, Kirk S, Whitten, David G
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 24.08.2011
• Subjects: Anti-Infective Agents - chemistry; Anti-Infective Agents - pharmacology; Cations - chemistry; Electrolytes - chemistry; Electrolytes - pharmacology; Gram-Negative Bacteria - drug effects; Gram-Positive Bacteria - drug effects; Light; Microscopy, Fluorescence; Polymers - chemistry; Polymers - pharmacology; Quaternary Ammonium Compounds - chemistry; Singlet Oxygen - chemistry; Singlet Oxygen - toxicity; Ultraviolet Rays; antimicrobial; antibacterial; amplified quenching; light activated biocides; singlet oxygen; conjugated polyelectrolytes
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/am200644g

This Spotlight on Applications provides an overview of a research program that has focused on the development and mechanistic study of cationic conjugated polyelectrolytes (CPEs) that function as light- and dark-active biocidal agents. Investigation has centered on poly-(phenylene ethynylene) (PPE) type conjugated polymers that are functionalized with cationic quaternary ammonium solubilizing groups. These polymers are found to interact strongly with Gram-positive and Gram-negative bacteria, and upon illumination with near-UV and visible light act to rapidly kill the bacteria. Mechanistic studies suggest that the cationic PPE-type polymers efficiently sensitize singlet oxygen (1O2), and this cytotoxic agent is responsible for initiating the sequence of events that lead to light-activated bacterial killing. Specific CPEs also exhibit dark-active antimicrobial activity, and this is believed to arise due to interactions between the cationic/lipophilic polymers and the negatively charged outer membrane characteristic of Gram-negative bacteria. Specific results are shown where a cationic CPE with a degree of polymerization of 49 exhibits pronounced light-activated killing of E. coli when present in the cell suspension at a concentration of 1 μg mL–1.