Amino Acid Block Copolymers with Broad Antimicrobial Activity and Barrier Properties.

Antimicrobial properties of a long-chain, synthetic, cationic, and hydrophobic amino acid block copolymer are reported. In 5 and 60 min time-kill assays, solutions of K L block copolymers (poly(l-lysine·hydrochloride) -b-poly(l-leucine) ) at concentrations of 10-100 µg mL show multi-log reductions in colony forming units of Gram-positive and Gram-negative bacteria, as well as yeast, including multidrug-resistant strains. Driven by association of hydrophobic segments, K L copolymers form viscous solutions and self-supporting hydrogels in water at concentrations of 1 and 2 wt%, respectively.