Self-Assembling Peptide Dendron Nanoparticles with High Stability and a Multimodal Antimicrobial Mechanism of Action

Abstract

Self-assembling nanometer-scale structured peptide polymers and peptide dendrimers have shown promise in biomedical applications due to their versatile properties and easy availability. Herein, self-assembling peptide dendron nanoparticles (SPDNs) with potent antimicrobial activity against a range of bacteria were developed based on the nanoscale self-assembly of an arginine-proline repeat branched peptide dendron bearing a hexadecanoic acid chain. The SPDNs are biocompatible, and our most active peptide dendron nanoparticle, C₁₆-3RP, was found to have negligible toxicity after both <i>in vitro</i> and <i>in vivo</i> studies. Furthermore, the C₁₆-3RP nanoparticles showed excellent stability under physiological concentrations of salt ions and against serum and protease degradation, resulting in highly effective treatment in a mouse acute peritonitis model. Comprehensive analyses using a series of biofluorescence, microscopy, and transcriptome sequencing techniques revealed that C₁₆-3RP nanoparticles kill Gram-negative bacteria by increasing bacterial membrane permeability, inducing cytoplasmic membrane depolarization and drastic membrane disruption, inhibiting ribosome biogenesis, and influencing energy generation and other processes. Collectively, C₁₆-3RP nanoparticles show promising biocompatibility and <i>in vivo</i> therapeutic efficacy without apparent resistance development. These advancements may facilitate the development of peptide-based antibiotics in clinical settings.