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.