An environmentally benign antimicrobial nanoparticle based on a silver-infused lignin core

Area of Science:

• Materials Science
• Nanotechnology
• Environmental Science

Background:

• Silver nanoparticles (AgNPs) exhibit antibacterial properties but raise environmental concerns due to their persistence.
• Developing sustainable and biodegradable antimicrobial agents is crucial for reducing environmental impact.

Purpose of the Study:

• To create a biodegradable and environmentally friendly alternative to conventional silver nanoparticles.
• To investigate the antimicrobial efficacy and toxicity of novel lignin-based nanoparticles infused with silver ions.

Main Methods:

• Synthesis of lignin nanoparticles infused with silver ions and coated with a cationic polyelectrolyte.
• Evaluation of antimicrobial activity against a broad spectrum of bacteria, including resistant strains.
• Assessment of particle adhesion to bacterial membranes and silver ion release kinetics.
• Toxicity screening via high-throughput assays compared to metallic silver nanoparticles and silver nitrate.

Main Results:

• The developed lignin-based nanoparticles demonstrated significant antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, and Ralstonia sp.
• The cationic polyelectrolyte coating enhanced particle adhesion to bacterial cell membranes.
• Ion depletion studies indicated a time-limited bioactivity due to silver ion desorption, suggesting reduced environmental persistence.
• Toxicity assessments showed no increased toxicity compared to equivalent masses of metallic silver nanoparticles or silver nitrate.

Conclusions:

• Lignin nanoparticles infused with silver ions represent a biodegradable and green alternative to traditional silver nanoparticles.
• This approach aligns with green chemistry principles, offering enhanced antimicrobial activity with a reduced environmental footprint.
• The time-limited bioactivity due to controlled silver ion release is a key feature for environmental safety.