Amino Acid Block Copolymers with Broad Antimicrobial Activity and Barrier Properties

Abstract

Abstract 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 100 L 40 block copolymers (poly( l ‐lysine·hydrochloride) 100 ‐ b ‐poly( l ‐leucine) 40 ) at concentrations of 10–100 µg mL −1 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 100 L 40 copolymers form viscous solutions and self‐supporting hydrogels in water at concentrations of 1 and 2 wt%, respectively. These K 100 L 40 preparations provide an effective barrier to microbial contamination of wounds, as measured by multi‐log decreases of tissue‐associated bacteria with deliberate inoculation of porcine skin explants, porcine open wounds, and rodent closed wounds with foreign body. Based on these findings, amino acid copolymers with the features of K 100 L 40 can combine potent, direct antimicrobial activity and barrier properties in one biopolymer for a new approach to prevention of wound infections. image