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Antimicrobial activity of fluorescent Ag nanoparticles
R K Bera1, S M Mandal, C R Raj
1Department of Chemistry, Indian Institute of Technology, Kharagpur, India.
Letters in Applied Microbiology
|January 28, 2014
Summary
Fluorescent silver nanoparticles (nAg-Fs) of 1.5 nm exhibit superior antimicrobial activity against bacteria and fungi compared to larger nanoparticles. Their enhanced efficacy stems from intracellular activity, driven by size and shape-dependent cell penetration.
Area of Science:
- Nanotechnology
- Microbiology
- Materials Science
Background:
- Silver nanoparticles (AgNPs) are recognized for their antimicrobial properties.
- Understanding the influence of nanoparticle size and shape on antimicrobial activity is crucial for developing effective agents.
Purpose of the Study:
- To investigate and compare the antimicrobial activity of fluorescent Ag nanoparticles (nAg-Fs) of 1.5 nm with AgNPs of varying sizes and shapes.
- To elucidate the mechanism underlying the antimicrobial action of nAg-Fs.
Main Methods:
- Antimicrobial activity testing against Gram-positive bacteria, Gram-negative bacteria, and fungal strains.
- Mechanism investigation using fluorescence microscopy and cytoplasmic material release assays.
Main Results:
- Fluorescent Ag nanoparticles (1.5 nm) demonstrated significantly higher antimicrobial activity than larger AgNPs.
- nAg-Fs localized intracellularly, with their activity primarily originating from within the microbial cell.
- Smaller nAg-Fs showed minimal cytoplasmic release but maximal antimicrobial effect, suggesting efficient cell penetration.
Conclusions:
- Antimicrobial activity of AgNPs is strongly dependent on particle size and shape.
- 1.5 nm fluorescent Ag nanoparticles possess superior antimicrobial potential due to enhanced cell penetration and intracellular activity.
- These findings support the development of nAg-Fs as novel antimicrobial agents.
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