Synthesis, characterization and bactericidal activity of silica/silver core-shell nanoparticles

Area of Science:

• Materials Science
• Nanotechnology
• Biomedical Engineering

Background:

• Antibiotic resistance is a growing global health threat.
• Novel antimicrobial agents are urgently needed.
• Core-shell nanoparticles offer unique properties for biomedical applications.

Purpose of the Study:

• To synthesize and characterize silica/silver core-shell nanoparticles (NPs).
• To evaluate the antibacterial efficacy of these NPs against Gram-positive and Gram-negative bacteria.
• To explore their potential as antibiotic alternatives.

Main Methods:

• Silica core particles (~300 nm) were coated with silver nanoparticles via electroless reduction.
• Characterization included X-ray diffraction, SEM, EDX, and UV-Vis spectroscopy.
• Antibacterial activity was assessed using the broth microdilution method against Bacillus subtilis and Escherichia coli ATCC25922.

Main Results:

• Silica/silver core-shell NPs were successfully synthesized with silver NP sizes ranging from 16-35 nm.
• Antibacterial activity was more pronounced against E. coli than B. subtilis.
• Minimal inhibitory concentrations ranged from 7.8 to 250 μg/mL, dependent on silver loading.

Conclusions:

• Silica/silver core-shell NPs demonstrate significant bactericidal activity.
• These NPs are effective against both Gram-positive and Gram-negative bacteria, including antibiotic-resistant strains.
• The findings suggest their potential application in medical devices for controlling pathogenic bacteria.