Structure–Activity Study of Antibacterial Poly(ester urethane)s with Uniform Distribution of Hydrophobic and Cationic Groups

Infections associated with antibiotic-resistant bacteria have become a threat to the global public health. Antimicrobial polymers, which are synthetic mimics of antimicrobial peptides, have gained increasing attention, as they may have a lower chance of inducing resistance. The cationic–hydrophobic balance and distribution of cationic and hydrophobic moieties of these polymers is known to have a major effect on antimicrobial activity. We studied the properties of a series of facially amphiphilic antimicrobial surfactant-like poly(ester urethane)s with different hydrophobic pendant groups (P1, P2, and P3) and cationic groups distributed uniformly along the polymer chain. These polymers exhibited bactericidal activity against Gram-negative Escherichia coli and Pseudomonas aeruginosa, as well as Gram-positive Staphylococcus aureus and Staphylococcus epidermidis. Microscopy and dye release assays demonstrated that these polymers cause membrane disruption, which is dependent on the cationic–hydrophobic ratio i...