CAT and neoplasm: The catalase-imprinted shell can selectively inhibit the activity of catalase to elevate H2O2 level, which could be converted into •OH under the catalysis of Fe ions released by Fe3O4/Fe core, triggering apoptosis to effectively kill MCF-7, 293T, and Hela tumor cells combined with the near-infrared light photothermal effect of the polydopamine layer.