Hydrophobic group modification for constructing self-assembling antimicrobial peptide derivatives with superior antimicrobial performance

The health risks associated with antibiotic resistance underscore the urgent need to develop novel antibiotic alternatives. Here, we constructed self-assembling antimicrobial peptide derivatives (AMPDs) with broad-spectrum and efficient antimicrobial activity by modifying AMP Ce(1–8) with hydrophobic groups. The results showed that the longer length fatty acid chain (more than 10 carbon numbers) modifications could drive lipopeptide self-assembly, and the hydrophobic interactions between fatty acid chains were the main driving force for self-assembly. The geometric means of the minimum inhibitory concentrations of the designed lipopeptides showed an approximately “U-shaped” relationship with the carbon numbers of the fatty acid chains, and the activity of the aromatic group-modified AMPs increased with increasing hydrophobicity of the aromatic groups. Among these AMPDs, C12Ce, C14Ce and FmocCe exhibited potent antimicrobial activity, with 8- to 12-fold increase in average antimicrobial activity compared with Ce(1–8). In addition, they had high selectivity and good stability. Antimicrobial mechanistic studies indicated that the self-assembled AMPDs disassembed into monomers when interacting with bacterial membranes, and then their hydrophobic tails inserted into the bacterial membranes, thereby disrupting cell membrane integrity. Furthermore, the self-assembling AMPDs could bind to bacterial genomic DNA and promote ROS generation, leading to bacterial death via multimodal mechanisms of action. Collectively, this work elucidates the effects of hydrophobic group modifications on the structure and activity of AMPDs, and reveals the self-assembly and antimicrobial mechanism of self-assembling AMPDs, providing theoretical basis and guidance for the development of peptide-based antimicrobial nanomaterials.