Nano-bio control of bacteria: A novel mechanism for antibacterial activities of magnetic nanoparticles as a temporary nanomagnets

The aim of this study is to investigate the role of interaction pattern between the Fe3O4 exposed by magnetic field as a temporary nanomagnets (TNMs) against bacterial interfaces, affecting antimicrobial trends of TNMs. The magnetite nano particles were prepared by the coprecipitation of Fe3+ and Fe2+ ions. The Fe3O4 nanopartides without any modification is called MNPs and Fe3O4 nanoparticles treated in the magnetic field is called TNMs. Functionalization by azo compounds using 3-Amino propyl triethoxysilane as a linker resulted in azo-compound @ MNPs. Azo-compound @ TNMs is a temporary nanomagnets treated by external magnetic field and during all tests it has magnetic property. The structural and magnetic properties of magnetic nanomaterials are identified by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) instruments. FT-IR and XRD were also used for the identification of these structures. All of the antibacterial tests were performed using MNPs and TNMs against two Gram positive and two Gram negative bacterial species. It is determined that the exposing of magnetic fields to magnetic nanoparticles can change the biological activity and increase the bacteriostaticity of these nano composites in bacterial medium. The TNMs may serve as a useful model system to apply electromagnetic interactions of Nano particles in biological system. Since TNMs are very unstable and oxidized in aqueous solution, surface modification of TNMs is crucial for biomedical applications. Functionalizations of TNMs by azo compounds protect them from red-ox reactions and improve their stability making nanoparticles better antibacterial nanocomposite. (C) 2017 Published by Elsevier B.V.