With the increased prevalence of antibiotic-resistant infections, there is an urgent need for innovative antimicrobial treatments. One such area being actively explored is the use of self-assembling cationic polymers. This relatively new class of materials was inspired by biologically pervasive cationic host defense peptides. The antimicrobial action of both the synthetic polymers and naturally occurring peptides is believed to be complemented by their three-dimensional structure. In an effort to evaluate shape effects on antimicrobial materials, tribloc
k polymers were polymerized from an assembly directing terephthalamide-bisurea core. Simple changes to this core, such as the addition of a methylene spacer, served to direct self-assembly into distinct morphologies鈥攕pheres and rods. Computational modeling also demonstrated how subtle core changes could directly alter urea stac
king motifs manifesting in unique multidirectional hydrogen-bond networ
ks despite the vast majority of material consisting of poly(lactide) (interior bloc
k) and cationic polycarbonates (exterior bloc
k). Upon testing the spherical and rod-li
ke morphologies for antimicrobial properties, it was found that both possessed broad-spectrum activity (Gram-negative and Gram-positive bacteria as well as fungi) with minimal hemolysis, although only the rod-li
ke assemblies were effective against
Candida albicans.
Keywords:
supramolecular assemblies; biodegradable polymers; antimicrobial; broad-spectrum activity; clinically isolated microbes; multidrug resistance