Green synthesis of biogenic Cu/Fe3O4 nanocomposite using the Eriobotrya japonica seed extract against pathogenic bacteria

•Biogenic Cu/Fe3O4 nanocomposite was green synthesized using Eriobotrya japonica seed extract without addition of any chemical reducing agents or surfactants with an average size of 35 nm.•Optimization the synthesis factors, such as, cation concentrate, the mass of plant extract, mass of Fe3O4 and extraction temperature, on the size of Cu/Fe3O4 nanocomposite.•Regardless of the many advances in the synthesis of Fe3O4 NPs, many challenges remain in their biomedical applications. Iron oxide nanoparticles have toxic properties for cells and microorganisms. Therefore, to use these nanoparticles, it is necessary to cover their surface with hydrophilic and biocompatible compounds that increase the effectiveness and half-life (t1/2) of these particles. Owing to its high biocompatibility and remarkable antibacterial properties, copper has received a lot of attention as a coating agent [31]. As well as Cu nanoparticle act as an antimicrobial agent and is much toxic to a microorganism such as bacteria and nontoxic to cells, owing to these functions copper is considered an efficient bactericidal metal. However, a few studies have been performed on green synthesis of Cu/Fe3O4 composite [32].•For a general conclusion, synthesis of nanocomposites depends mainly on methods that have toxic chemicals and relatively hard reaction conditions that is a great drawback to the environment and human health. Therefore, in this research, to biosynthesize Cu/Fe3O4 nanocomposite, the seed extract of Eriobotrya japonica was used as a capping and reducing agent. Biocompatibility, smaller size, reduction of nanoparticle toxicity due to vegetation around nanoparticles, low synthesis cost, improvement of the physicochemical and antibacterial properties of Fe3O4 NPs, existence of different functional groups on nanoparticle surface, shape uniformity and also nanoparticle size is one of the advantages of biosynthesis. The end part of the paper includes the evaluation of the antibacterial activity of Cu/Fe3O4 nanocomposite via disk diffusion test and minimum inhibitory concentration (MIC) method. In this work, we designed an environmentally sound approach for green biosynthesis of the Cu/Fe3O4 with antibacterial effects using Eriobotrya japonica seed extract as reducing and stabilizing agents. The effects of synthesis factors, such as cation concentrate, the mass of plant extract, mass of Fe3O4 and extraction temperature, on the size of Cu/Fe3O4 nanocomposite were considered and optimized. Dif