Auger Electrons Constructed Active Sites on Nanocatalysts for Catalytic Internal Radiotherapy

Abstract Excess electrons play important roles for the construction of superficial active sites on nanocatalysts. However, providing excess electrons to nanocatalysts in vivo is still a challenge, which limits the applications of nanocatalysts in biomedicine. Herein, auger electrons (AEs) emitted from radionuclide 125 ( 125 I) are used in situ to construct active sites in a nanocatalyst (TiO 2 ) and the application of this method is further extended to cancer catalytic internal radiotherapy (CIRT). The obtained 125 I‐TiO 2 nanoparticles first construct superficial Ti 3+ active sites via the reaction between Ti 4+ and AEs. Then Ti 3+ stretches and weakens the OH bond of the absorbed H 2 O, thus enhancing the radiolysis of H 2 O molecules and generating hydroxyl radicals (•OH). All in vitro and in vivo results demonstrate a good CIRT performance. These findings will broaden the application of radionuclides and introduce new perspectives to nanomedicine.