Fig. 1

Synthesis and characterization of H-MnO2-PEG. a A scheme indicating the step-by-step synthesis of H-MnO2-PEG nanoparticles and the subsequent dual-drug loading. b, c A TEM image (b) and a magnified TEM image (c) of H-MnO2-PEG. d HAADF-STEM image and elemental mapping for H-MnO2-PEG. e A photo of the 500 mL reaction vessel for preparation of H-MnO2 in a large scale. f Digital picture showing the gram-scale production of H-MnO2 nanoshells in one reaction. g A representative TEM image of H-MnO2 nanoshells prepared in the gram-scale