Fabrication, bacteriostasis and plant growth properties researches of ultrasmall particle sizes of Ag synergistic with Fe3O4/Cu/CuO nanocomposites

Nano-silver (Ag) with ultra-small particle sizes have strong antibacterial activity because it can pass through the bacterial cell wall and enter the internal environment, causing irreversible damage to bacteria, but the disadvantages such as easy agglomeration and high toxicity alone limit its application. Therefore, In this study, by loading ∼3 nm ultrasmall particle sizes Ag (QDs) on the Fe3O4/Cu/CuO (FC) surface, core-shell type Fe3O4/Cu/CuO@Ag nanocomposite (FAN) was created. We used commercially available Bordeaux liquid (BM) as a control and targeted Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) to investigate the antibacterial activity of the material and its antibacterial mechanism. To examine the biocompatibility of materials with human cells and their effect on plant growth, the model plant employs mung bean as its objectives. The results showed that FAN can effectively inhibit E. coli and S. aureus for up to 99.99 % within 20 min, which is ten times greater than BM. It had a delaying effect on the adaptation period and logarithmic phase of bacterial growth, and could effectively destroy bacterial cell walls and respiratory enzymes. According to biocompatibility studies, FAN has little effect on lactation cells and can promote mung bean germination, root growth, and chlorophyll content with twice the efficiency of BM. This research opens the door to inhibition agents for bacterial control in applications.