Fig. 3.

The antibacterial activity and corresponding mechanism of MMHP NPs toward broad-spectrum bacteria. (A) The antibacterial activity of PBS, MN + HP, and MMHP NPs toward different bacterial strains. (B) The optical density (600 nm) of PBS, MN + HP, and MMHP NPs under neutral or ROS (H₂O₂) environment. (C) Varied optical densities (600 nm) of PBS, MN + HP, and MMHP NPs treated by PBS, MN + HP, and MMHP NPs at different ROS concentrations (0.01 to 0.08 mM). (D) The optical density (600 nm) of PBS, MN + HP, and MMHP NPs under varied ATP concentrations. (E) The optical density (600 nm) of PBS, MN + HP, and MMHP NPs during varied ROS concentrations (0.01 to 0.04 mM). (F) The Mn²⁺, Cu²⁺, Mg²⁺ and Fe³⁺ concentrations of PBS-, HP-, and MMHP NP-treated S. aureus. (G) The molecular docking between Mg²⁺ and HP. (H) The TEM image of S. aureus and E. coli after PBS and MMHP NP treatments. (I) The antibacterial mechanism of MMHP NPs. (A) to (F) were analyzed with one-way ANOVA. n.s., not significant.