Synthesis and characterization of magnetite/Alyssum homolocarpum seed gum/Ag nanocomposite and determination of its antibacterial activity

Due to applications of silver nanoparticles (Ag NPs) especially in advanced science fields, it is important to produce Ag antibacterial nanocomposites with enhanced antibacterial activity and reusability. Over the past decade researches about natural polymers have emphasized the use of them as nanoparticles coating. In this work, a novel core-shell antibacterial agent was synthesized through a three-step procedure. Fe3O4 nanoparticles (Fe3O4 NPs) were synthesized and coated with a natural polymer called Alyssum homolocarpum seed gum (AHSG). Ag NPs were immobilized on the AHSG resulting in formation of the new nanocomposite with improved antimicrobial properties. The immobilization of AgNPs prevents the release of toxic Ag+ ions. The Fe3O4@AHSG@Ag nanocomposite could easily be separated from medium using an external magnetic field due to presence of the Fe3O4 superparamagnetic nanoparticles. The as-synthesized nanocomposite was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, vibrating sample magnetometer and dynamic light scattering. The results showed that the magnetic nanocomposite was synthesized and coated successfully. Finally, results of disk diffusion method demonstrated that the nanocomposite exhibits excellent antibacterial activity against gram-positive and gram-negative bacteria. (c) 2019 Elsevier B.V. All rights reserved.