Preparation of amino silane magnetic nanocomposite by the sol-gel process and investigation of its antibacterial activity

Abstract

The results of a comparative investigation on microstructure and magnetic characteristics of silane magnetic nanocomposites coated with silver nanoparticles (AgNPs) are presented. The authors used tetraethyl orthosilicate (TEOS) with (3-aminopropyl) triethoxysilane (APTES) to improve the antibacterial properties of AgNPs. On the basis of this approach, TEOS-APTES polymer was made by the sol-gel method. A layer of the polymer was set on the magnetic core of Fe 3 O 4 NPs and then AgNPs were coated on the TEOS-APTES surface. Therefore, the core-shell structure of the Fe 3 O 4 /TEOS-APTES/Ag polymer nanocomposite was synthesised. To characterise the crystal morphology, structure, and size of nanocomposites, various techniques and experiments including Fourier transform infrared spectroscopy, X-ray diffraction, field-emission scanning electron microscope, dynamic light scattering, and transmission electron microscope were used. Vibrating sample magnetometer showed the magnetic properties of the samples. Finally, antibacterial activity against Gram-negative and Gram-positive bacteria including Escherichia Coli (American Type Culture Collection (ATCC) 35218), Salmonella typhimurium (ATCC 14028), Staphylococcus aureus (ATCC 292113) and Bacillus cereus (ATCC 14579) was showed by the disc diffusion analysis. The results indicated the uniform distribution of AgNPs on the polymer surface. Fe 3 O 4 /TEOS-APTES/Ag nanocomposite showed much better antibacterial activity in comparison with AgNPs only.