Fig. 4. Bactericidal activity in vivo. (a) In vivo fluorescence images of MDR PA lung-infected mice at various time points post-intravenous injection of ICG@HMnO₂ and ICG@HMnO₂@NM. (b) Lung bacterial loads in mice post-treatment with saline (control), HMnO₂@NM, PMB and PMB@ HMnO₂@NM. (c) Giemsa staining results of lung tissue after treatment with saline (control), HMnO₂@NM, PMB and PMB@HMnO₂@NM. Scale bars: 20 μm. (d) H & E staining of lung tissue after treatment with saline (control), HMnO₂@NM, PMB and PMB@HMnO₂@NM. Scale bars: 20 μm. (e) Serum levels of IL-6 and TNF-α collected after treated with saline (control), HMnnO₂@NM, PMB and PMB@HMnO₂@NM. (f) Percentage survival of pneumonia mice treated with saline (control), HMnO₂@NM, PMB and PMB@HMnO₂@NM (n = 6, *p < 0.05, **p < 0.01, ***p < 0.001, n.s. means no significance. Data are expressed in mean ± SD).