Antibacterial Silver-Conjugated Magnetic Nanoparticles: Design, Synthesis and Bactericidal Effect
The aim was to design and thoroughly characterize monodisperse Fe3O4@SiO2-Ag nanoparticles with strong antibacterial properties, which makes them a candidate for targeting bacterial infections.
The monodisperse Fe3O4 nanoparticles were prepared by oleic acid-stabilized thermal decomposition of Fe(III) oleate; the particles were coated with silica shell using a water-in-oil reverse microemulsion, involving hydrolysis and condensation of tetramethyl orthosilicate. Resulting Fe3O4@SiO2 particles were modified by (3-mercaptopropyl)trimethoxysilane to introduce 1.1 mmol SH/g. Finally, the Fe3O4@SiO2-SH nanoparticles were decorated with silver nanoclusters formed by reduction of silver nitrate with NaBH4. The particles were analyzed by FTIR, X-ray photoelectron and atomic absorption spectroscopy, dynamic light scattering and vibrating sample magnetometry. The antibacterial activity of the Fe3O4@SiO2 and Fe3O4@SiO2-Ag nanoparticles was tested against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria cultivated on Luria agar plates or in Luria broth.
The superparamagnetic Fe3O4@SiO2-Ag nanoparticles (21 nm in diameter; saturation magnetization 26 A∙m2/kg) were successfully obtained and characterized. Inhibitory and toxic effects against bacteria were documented by incubation of the Fe3O4@SiO2-Ag nanoparticles with Staphylococcus aureus and Escherichia coli.
The combination of magnetic properties together with bactericidal effects is suitable for the disinfection of medical instruments, water purification, food packaging, etc.
KEY WORDSantibacterial activity magnetic nanoparticles silica shell thiol-functionalization
Atomic absorption spectrometer
Colony forming units
Dynamic light scattering
- E. coli
- Igepal CO-520
Luria agar plates
No treatment controls
Phosphate buffered saline
- S. aureus
Transmission electron microscope
X-ray photoelectron spectroscopy
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