The dark bactericidal mechanisms of poly(phenylene ethynylene) (PPE)-based cationic conjugated polyelectrolytes (CPE) and oligo-phenylene ethynylenes (OPE) have been investigated using electronic/optical microscopy and small angle X-ray scattering (SAXS). The ultrastructural analysis shows that the polymeric PPE-Th significantly remodels the bacterial cell wall followed by possible collapse of the bacterial cytoplasm membrane. In contrast, the oligomeric End-Only OPE (EO-OPE) possesses potent bacteriolysis activity, which efficiently disintegrates the bacterial cytoplasm membrane and induces the release of cytoplasma content. Using single giant vesicles and SAXS, we demonstrated that the membrane perturbation mechanism of the EO-OPE against model bacterial membranes results from a three-dimensional membrane phase transition.  The biocidal pathways of the CPE and OPE compounds function by via compromising the bacterial structural integrity make it difficult for the bacteria to develop resistance. The correlation of quantitative dark biocidal activity with structure and type of perturbation of the cell wall will be reported.

When worlds collide: Interactions at the interface between biological systems and synthetic cationic polyelectrolytes and oligomers

243rd National Meeting (2012)

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