A self-assembled amino acid-based hydrogel with broad-spectrum antibacterial activity

Amino acid-based hydrogels with broad-spectrum antibacterial properties are increasingly popular alternatives to existing treatments in the fight against bacterial infection. Here, an amino acid-based hydrogel formed by the self-assembly of N-(9-fluorenylmethoxycarbonyl)-(L)-Leucine (Fmoc-L) and Fmoc-(L)-Lysine (Fmoc-K) is reported. The Fmoc-L/Fmoc-K hydrogel, which consisted of twisted nanobelts, displayed antibacterial activity against Gram-positive S. aureus, B. subtilis, L. monocytogenes, and Gram-negative E. coli, Sh. sonnei. Specifically, inhibition rates of 97%, 100%, 44%, 45%, and 32% were achieved against S. aureus, B. subtilis, L. monocytogenes, E. coli, and Sh. sonnei after incubation with 4 mM of an Fmoc-L/Fmoc-K hydrogel with the molar ratio of 3:1 for 2 h, respectively. The inhibition rates against E. coli and Sh. sonnei reached 80% and 55% after treatment with 10 mM hydrogel, respectively. The antibacterial activity of hydrogels was time-dependent and enhanced with the prolongation of time. Additionally, the antibacterial activity was easily tailored by modifying the molar ratio of Fmoc-L and Fmoc-K. It was found that Fmoc-L/Fmoc-K hydrogel targeted and destroyed the bacterial cell membrane, causing cytoplasmic leakage and eventually cell death. Moreover, the hydrogel also displayed antibacterial action by inducing the agglomeration of S. aureus. This work demonstrates the potential of amino acid-based hydrogels as a new class of effective [GRAPHICS] .

Automated summary

Amino acid-based hydrogels formed by Fmoc-L and Fmoc-K self-assembly demonstrated significant antibacterial activity against various bacteria, with the ability to tailor the antibacterial effect by modifying the molar ratio of amino acids. This study highlights the potential of amino acid-based hydrogels as effective antibacterial agents.