Design of a two-dimensional interplanar heterojunction for catalytic cancer therapy

Chemodynamic therapy relies on Fenton or Fenton-like reactions to produce hydroxyl radical in the tumor region. Here the authors design a two-dimensional interplanar heterojunction with in situ hydroxyl radical generation under ultrasound irradiation, showing anti-cancer activity in preclinical models. Limited substrates content is a major hurdle dampening the antitumor effect of catalytic therapy. Herein, a two-dimensional interplanar heterojunction (FeOCl/FeOOH NSs) with center dot OH generation under ultrasound irradiation is fabricated and utilized for catalytic cancer therapy. This interplanar heterojunction is prepared through replacing chlorine from iron oxychloride with hydroxyl. Benefiting from the longer hydroxyl bond length and enhanced affinity with water, the alkali replacement treatment integrates interplanar heterojunction synthesis and exfoliation in one step. In particular, a build-in electric field facilitated Z-scheme interplanar heterojunction is formed due to the aligning Fermi levels. The holes on the valence band of FeOCl have great ability to catalyze O-2 evolution from H2O, meanwhile, the generated O-2 is immediately and directly reduced to H2O2 by the electrons on the conductive band of FeOOH. The self-supplying H2O2 ability guarantees efficient center dot OH generation via the Fenton-like reaction catalyzed by FeOCl/FeOOH NSs, which exhibits excellent anti-tumor performance.