Stimuli-responsive antimicrobial polymer systems: From structural design to biomedical applications

Bacterial infections and drug-resistant evolution have seriously threatened public health. Stimuli-responsive antimicrobial materials have been rapidly developed to address the evolving challenges posed by multi-drug-resistant bacteria. Among various materials, polymer-based stimuli-responsive systems stand out thanks to their structural design flexibility, functional diversity, decreased systemic toxicity, and enhanced therapeutic effects compared with free drugs. In this review, we present the latest advances in stimuli-responsive antimicrobial polymer systems, summarizing their molecular structures and design principles across exogenous and endogenous stimulus types. Exogenous stimuli offer precise spatiotemporal control triggered by temperature, light, magnetic, salt, etc. Endogenous stimuli are in-situ biomarkers in the infection environment, such as pH, redox, bacterial secretions, etc. In the aim of developing antimicrobial material with high selectivity, we also summarize antimicrobial recognition strategies that enhance drug targeting efficiency. Finally, the challenges in current stimuli-responsive antimicrobial polymeric systems are discussed, opening up prospects for next-generation intelligent antimicrobial materials with enhanced efficacy, biosafety and pathogen-targeting precision.