Inherently self-sterilizing charged multiblock polymers that kill drug-resistant microbes in minutes

Abstract

Drug-resistant microbes loom as a growing threat to global healthcare by greatly increasing the risk of hospital-acquired infections that could ultimately become fatal, especially for elderly, injured and immune-compromised patients. As a consequence, several materials-related antimicrobial strategies have been developed to mitigate this ubiquitous concern, resulting in different levels of success and, in some cases, introducing deleterious complications to environmental safety. Here, we demonstrate that charged multiblock polymers wherein the midblock is selectively sulfonated, and therefore hydrophilic and water-swellable, inherently provide self-sterilizing surfaces that rapidly act (killing more than 99.9999% in just 5 min) against a wide range of Gram-positive and -negative bacteria, three of which are antibiotic-resistant. This surprising response, which depends on the degree of midblock sulfonation, is attributed to a dramatic reduction in surface pH level that is remarkably effective against microbes with a typically anionic outer membrane. These polymers, suitable for use in biomedical applications, smart textiles, separation membranes, commodity fixtures, and food packaging, are equally effective against infectious virus strains. Although the antimicrobial efficacy of these polymers is progressively diminished through complexation of sulfonic acid groups with cationic species during cyclic exposure to electrolyte solutions, these thermoplastic elastomers can be fully rejuvenated to their maximum performance level by relatively short immersion in acidic solutions. As a highly promising addition and alternative design paradigm to the expanding arsenal of antimicrobial materials, these midblock-sulfonated multiblock polymers constitute a facile, inexpensive, comprehensive, and environmentally-benign preventative route by which to combat the worldwide proliferation of drug-resistant microbes.