Development of ZnO/Ag nanoparticles supported polydopamine-modified montmorillonite nanocomposites with synergistic antibacterial performance

Nanocomposites are effective methods for the treatment of microbial infections. In this work, zinc oxide nanoparticles and silver nanoparticles were synthesized by a simple and mild method, and successfully loaded on polydopamine-modified montmorillonite (PDAMt) to prepare nanocomposites (ZnO/Ag/PDA-Mt) with potent antibacterial ability. The transmission electron microscope (TEM) showed that the nanoparticles in ZnO/Ag/PDA-Mt were quasi-spherical, and the particle size ranged from 5 nm to 45 nm. The energy dispersive spectroscopy (EDS)-mapping verified the presence of Zn, Ag, O, Al, Si and C elements in the synthesized ZnO/Ag/PDA-Mt. In addition, the antimicrobial activity of ZnO/Ag/PDA-Mt was also tested against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Due to the synergistic antibacterial effect between zinc oxide nanoparticles and silver nanoparticles, ZnO/Ag/PDA-Mt exhibited higher antiseptic activity than silver nanoparticles supported polydopamine-modified montmorillonite (Ag/PDA-Mt) and zinc oxide nanoparticles supported polydopamine-modified montmorillonite (ZnO/PDA-Mt). The biocompatibility of ZnO/Ag/PDA-Mt was evaluated by cytotoxicity assay. The results demonstrated that the ZnO/Ag/PDA-Mt nanocomposites have potential for antibacterial applications.