The emergence of antibiotic resistant bacteria or �superbugs� is rapidly the available treatment options. These new superbugs require newer antimicrobials which can overcome the existing or emerging resistance mechanisms of bacteria. This study focuses on new strategies to develop amphiphilic polymers as antimicrobial agents. These polymers are designed using cationic, amphiphilic structures and architectures as molecular frameworks to mimic the antimicrobial mechanism of host-defense peptides (HDPs) in the innate immune system. Our laboratory has developed cationic, amphiphilic random methacrylate copolymers as synthetic mimics of HDPs. The copolymers inhibited growth of a broad spectrum of bacteria including antibiotic-resistant strains without adverse toxicity to human cells. These polymers exert antimicrobial activity by disrupting bacterial cell membranes, in contrast to conventional antibiotics. We also prepared new amphiphilic di-block copolymers with cationic and hydrophobic blocks. The block copolymers showed selective activity to bacteria over human cells, and are much less hemolytic than their random copolymer counterparts. The di-block copolymer chains likely form single molecular micelles, in which the hydrophobic block aggregates and forms core domains in water, wrapped by the cationic polymer chain. This structure curtains the hydrophobic domains and prevents non-specific binding of polymers to human cells. These results suggest that both amphiphilic polymer structures and architectures play important roles in their antimicrobial mechanism.

Amphiphilic polymer structures and architectures for antimicrobial materials

245th National Meeting (2013)

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