Secondary Ammonium-Based Hyperbranched Poly(amidoamine) with Excellent Membrane-Active Property for Multidrug-Resistant Bacterial Infection

ACS Appl Bio Mater. 2022 Jul 18;5(7):3384-3395. doi: 10.1021/acsabm.2c00356. Epub 2022 Jun 28.


With the rapid emergence of microbial infections induced by "superbugs", public health and the global economy are threatened by the lack of effective and biocompatible antibacterial agents. Herein, we systematically design a series of secondary ammonium-based hyperbranched poly(amidoamine) (SAHBP) with different alkyl chain lengths for probing high-efficacy antibacterial agents. SAHBP modified with alkyl tails at the hyperbranched core could efficiently kill Escherichia coli and Staphylococcus aureus, two types of clinically important bacteria worldwide. The best SAHBP with 12-carbon-long alkyl tails (SAHBP-12) also showed high activity against problematic multidrug-resistant bacteria, including Pseudomonas aeruginosa and methicillin-resistant S. aureus (MRSA). Based on ζ potential, isothermal titration microcalorimetry (ITC), and membrane integrity assays, it is found that SAHBP-12 could attach to the cell membrane via electrostatic adsorption and hydrophobic interactions, following which the integrity of the bacterial cell wall and the cell membrane is disrupted, resulting in severe cell membrane damage and the leakage of cytoplasmic contents, finally causing bacterial cell death. Impressively, benefiting from excellent membrane-active property, SAHBP-12 exhibited robust therapeutic efficacy in MRSA-infected mice wounds. Moreover, SAHBP-12 also showed excellent biosafety in vitro and in vivo, which undoubtedly distinguished it as a potent weapon in combating the growing threat of problematic multidrug-resistant bacterial infections.

Keywords: antibacterial agent; antibacterial performance; bacterial infections; membrane-active property; multidrug resistance; secondary ammonium-based hyperbranched poly(amidoamine) (SAHBP).

MeSH terms

  • Ammonium Compounds* / pharmacology
  • Animals
  • Anti-Bacterial Agents / pharmacology
  • Bacteria
  • Bacterial Infections*
  • Escherichia coli
  • Methicillin-Resistant Staphylococcus aureus*
  • Mice
  • Microbial Sensitivity Tests
  • Polyamines


  • Ammonium Compounds
  • Anti-Bacterial Agents
  • Poly(amidoamine)
  • Polyamines