Fig. 3. Performance testing of HM in vitro. (a) Catalase-like property of HM: variations of the concentration of O₂ in H₂O₂ solutions (100 μm) with the addition of HM at various concentrations. (b) Degradation of HM: TEM images of HM incubated in PBS at pH levels of 6.5 and 7.4 for varying durations. (c) Percentages of retained MnO₂ after HM degradation over time in the presence of PBS at pH levels of 5.5, 6.5 and 7.4. (d) Percentages of HMME and DOX released from DH-HM@BSA over time in the presence of PBS at varying pH levels (7.4 and 6.5) with or without us irradiation. (e) Fluorescence intensities of so in different groups detected by SOSG. The date are expressed as means ± SD (n = 3) (***p < 0.001, **p < 0.01, and *p < 0.05).