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Cationic facially amphiphilic phenylene ethynylenes as host defense peptide mimics

Lachelle Arnt, University of Massachusetts Amherst


The goal of this research is to design molecules that capture the essential elements and biological properties of host defense peptides without the use of amino acids or peptide-like backbones. This is accomplished via a meta-phenylene ethynylene backbone with polar amine and nonpolar alkyl groups as side chains. These molecules are shown to form stable monolayers at the air-water interface with the polymer chains assuming an edge-on structure with the aromatic rings perpendicular to the water surface and the polar amines groups below the water surface. Furthermore, these molecules aggregate in solution with the addition of a non-solvent, as expected with facially amphiphilic molecules. When tested against biological systems, the result is promising: growth inhibition against a wide variety of bacteria at relatively low concentrations with minimal disruption towards red blood cells. The average minimal concentration needed to disrupt bacterial growth is 2 μg/mL and occurs in less than 5 minutes. Furthermore, tests indicate negligible evolution of bacterial resistance over a month-long experiment. Incorporation of these compounds into polymeric substrates proves to be an effective way of preventing bacterial growth on surfaces. Further probing the mode of action of these molecules shows results similar to many host defense peptides.

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Recommended Citation

Arnt, Lachelle, "Cationic facially amphiphilic phenylene ethynylenes as host defense peptide mimics" (2005). Doctoral Dissertations Available from Proquest. AAI3179853.