Scientific article: Killing bacteria

Polyaromatic light-interacting polymers can as environmentally-responsive polyelectrolytes switch between membrane-active and soluble forms. Developed as a potent antimicrobial that attacks the membrane and cell machinery of bacterial pathogens by colleagues at the University of New Mexico and the University of Texas, we have demonstrated the remarkable extent to which these polymers are antimicrobial, which was published in ACS Applied Materials & Interfaces. Further, we showed how the killing efficiency is often greatly enhanced by exposure to light.

Tremendous efforts have been devoted to the development of antimicrobial materials able to defeat new and antibiotic-resistant pathogens. Colleagues at the University of New Mexico (UNM) and the University of Texas at San Antonio have been investigating the properties of poly(phenylene ethynylene), polythiophene, and oligo(phenylene ethynylene) electrolytes for many years.

A collaboration with the Institute for Biologically Inspired Materials (BIMat) at BOKU was formed through the guest professorship of David G. Whitten (UNM). Our goal has been to exploit BIMat expertise to achieve greater understanding of how these polymers self-assemble into functional structures, interact with light, and function as antimicrobials.

Our first published work from this collaboration quantitatively evaluates the impressive efficacy of these polymers against laboratory strains of Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, and Escherichia coli, which all have antibiotic-resistant pathogenic forms.

Using cell plating with serial dilutions, we determined that planktonic bacteria suspensions exposed to the antimicrobials result in several log-kills after less than 10 min exposure both in the dark and under UV irradiation (360 nm) for all eight synthetic antimicrobials. In most trials, there is significantly higher killing under light-irradiation, indicating these materials may be used as versatile disinfectants.

The article is published in an ACS Applied Materials & Interfaces special issue on Advances in Biocidal Materials and Interfaces as “Quantitative Determination of Dark and Light-Activated Antimicrobial Activity of Poly(Phenylene Ethynylene), Polythiophene, and Oligo(Phenylene Ethynylene) Electrolytes.”