Silver coated anionic cellulose nanofiber composites for an efficient antimicrobial activity.

Area of Science:

• Materials Science
• Nanotechnology
• Biomaterials

Background:

• Cellulose nanofibers (CNFs) are versatile biomaterials with potential applications in various fields.
• Developing effective antimicrobial materials is crucial for healthcare and public safety.
• Silver nanoparticles (AgNPs) are known for their potent antimicrobial properties.

Purpose of the Study:

• To comparatively evaluate the antibacterial activity of silver-coated anionic cellulose nanocomposites before and after chemical reduction.
• To investigate the effect of chemical reduction on silver content, silver release, and antimicrobial efficacy.
• To characterize the structural and chemical properties of the synthesized nanocomposites.

Main Methods:

• Anionic cellulose nanofibers (CMC) were prepared from cellulose acetate nanofibers.
• Silver-coated cellulose nanocomposites (CMC-Ag) were synthesized using aqueous AgNO3.
• AgNPs/CMC nanocomposites were obtained by chemically reducing CMC-Ag with NaBH4.
• Nanocomposite characterization included FE-SEM, FTIR, XPS, and SEM-EDS.
• Antibacterial activity was assessed against S. aureus and E. coli using JIS L1902, 2008.

Main Results:

• SEM-EDS confirmed higher silver content in CMC-Ag compared to AgNPs/CMC.
• Antimicrobial tests showed a larger halo width (indicating higher silver release) for CMC-Ag.
• CMC-Ag exhibited superior antibacterial activity against both S. aureus and E. coli.
• Chemical reduction to AgNPs/CMC resulted in lower silver release and reduced antimicrobial efficacy.

Conclusions:

• The CMC-Ag nanocomposite, without chemical reduction, demonstrates enhanced antibacterial performance.
• Higher silver release from the CMC-Ag composite is directly correlated with its superior antimicrobial activity.
• These findings suggest that controlling silver state in cellulose nanocomposites is key to optimizing antimicrobial efficacy.