Preparation and characterization of SiO2/polydopamine/Ag nanocomposites with long-term antibacterial activity

Silver nanoparticles (Ag NPs) with diameter of approximately 10 nm were prepared by the reduction of silver nitrate using green synthesis, an eco-friendly approach. The synthesized Ag NPs were homogeneously deposited on silicon dioxide (SiO2) particles modified with dopamine, leading to the formation of SiO2/polydopamine (PD)/Ag nanocomposites (NCs) with a core–shell–satellite structure investigated by transmission electron microscopy. The Ag content of SiO2/PD/Ag NCs determined by inductively coupled plasma optical emission spectrometry was approximately 5.92 wt%. The antibacterial properties of both Ag NPs and SiO2/PD/Ag NCs against Vibrio natriegens (V. natriegens) and Erythrobacter pelagi sp. nov. (E. pelagi) were investigated by bacterial growth curves and inhibition zone. Compared to Ag NPs, the SiO2/PD/Ag NCs exhibited superior long-term antibacterial activity, attributed to its controlled release of Ag+ ions.