<p>As bacteria are developing stronger resistance, infections caused by <i>Escherichia coli</i> (<i>E. coli</i>) and <i>Staphylococcus aureus</i> (<i>S. aureus</i>) are becoming increasingly difficult to treat. Consequently, the preparation of targeted antibacterial hydrogel materials that possess high injectable mechanical strength as well as excellent antibacterial properties has drawn significant attention in the field of antibacterial research. In this paper, Fe₃O₄ particles were used as the magnetic core and shielded by a hydrophilic carbon (C) layer. Subsequently, on the surface of the C layer, a mesoporous polydopamine (MPDA) film with favorable biocompatibility was fabricated, and small-sized Ag nanoparticles (Ag NPs) possessing excellent antibacterial performance were modified thereon. Eventually, the above composite nanoparticles were mixed with pure polyvinyl alcohol (PVA) hydrogel to formulate an injectable antibacterial hydrogel. The antibacterial properties of Fe₃O₄@C@MPDA@Ag nanoparticles at varying concentrations were evaluated through in vitro experiments. The results demonstrated that the higher the concentration of Fe₃O₄@C@MPDA@Ag nanoparticles, the more remarkable the antibacterial effect would be. Moreover, the survival rates of Fe₃O₄@C@MPDA nanoparticles and Fe₃O₄@C@MPDA@Ag nanoparticles on HL-7702 cells were evaluated via in vitro cytotoxicity experiments. The results showed that the two nanoparticles had good biocompatibility. In addition, the antibacterial properties of Fe₃O₄@C@MPDA@Ag@PVA antibacterial hydrogel in mice has been researched. The results indicated that it has good antibacterial properties and wound healing properties.</p>