ε-Polylysine Nanoconjugates: Value-Added Antimicrobials for Drug-Resistant Bacteria

Area of Science:

• Nanotechnology
• Materials Science
• Microbiology

Background:

• Antimicrobial resistance (AMR) is a global health crisis with few new antibiotics developed.
• Existing antibiotics are becoming ineffective against critical bacterial pathogens.
• Drug-resistant infections necessitate novel therapeutic strategies.

Purpose of the Study:

• To design and evaluate novel nanocargos for combating drug-resistant bacteria.
• To assess the antibacterial efficacy and safety of gold nanoparticle (AuNP)-conjugated ε-polylysine (PLL) and octadecanethiol (C18) nanocargos.
• To investigate the potential of these nanocargos in preventing bacterial biofilm formation.

Main Methods:

• Conjugation of gold nanoparticles (AuNPs) with ε-polylysine (PLL) and octadecanethiol (C18) to create nanocargos.
• Testing nanocargos against reference strains of carbapenem-resistant Acinetobacter baumannii (CRAB) and methicillin-resistant Staphylococcus aureus (MRSA).
• Determining minimum inhibitory concentration (MIC), evaluating hemolytic and cytotoxic effects, and analyzing antibacterial mechanisms and antibiofilm activity.

Main Results:

• Nanocargos exhibited 15-20-fold higher antibacterial activity than free PLL against CRAB and MRSA.
• The minimum inhibitory concentration (MIC) ranged from 8 to 15 μg/mL for the nanoconjugates.
• Nanocargos demonstrated nonhemolytic and nontoxic properties towards mammalian cells and superior antibiofilm efficacy.

Conclusions:

• PLL-conjugated AuNP nanocargos are effective against critical drug-resistant bacteria.
• These nanocargos offer a promising, safe alternative to conventional antibiotics.
• Potential applications include preventing biofilm formation on medical devices and surgical instruments.