Polycationic Synergistic Antibacterial Agents with Multiple Functional Components for Efficient Anti-Infective Therapy

Multifunctional antibacterial photodynamic therapy is a promising method to combat regular and multidrug-resistant bacteria. In this work, eosin Y (EY)-based antibacterial polycations (EY-QEGED-R, R = -CH3 or -C6H13) with versatile types of functional components including quaternary ammonium, photosensitizer, primary amine, and hydroxyl species are readily synthesized based on simple ring-opening reactions. In the presence of light irradiation, such antibacterial polymers exhibit high antibacterial efficiency against both Escherichia coli and Staphylococcus aureus. In particular, EY-QEGED-R elicits a remarkable synergistic antibacterial activity owing to the combined photodynamic and quaternary ammonium antibacterial effects. Due to its rich primary amine groups, EY-QEGED-R also can be readily coated on different substrates, such as glass slides and nonwoven fabrics via an adhesive layer of polydopamine. The resultant surface coating of EY-QEGED-CH3 (s-EY-QEGED-CH3) produces excellent in vitro antibacterial efficacy. The plentiful hydroxyl groups impart s-EY-QEGED-CH3 with potential antifouling capability against dead bacteria. The antibacterial polymer coatings also demonstrate low cytotoxicity and good hemocompatibility. More importantly, s-EY-QEGED-CH3 significantly enhances in vivo therapeutic effects on an infected rat model. The present work provides an efficient strategy for the rational design of high-performance antibacterial materials to fight biomedical device-associated infections.