Modulating dual carrier-transfer channels and band structure in carbon nitride to amplify ROS storm for enhanced cancer photodynamic therapy.

Graphite carbon nitride (CN) eliminates cancer cells by converting HO to highly toxic •OH under visible light. However, its in vivo applications are constrained by insufficient endogenous HO, accumulation of OH and finite photocarriers. We designed Fe/N-CN, co-modified CN with nitrogen vacancies (N) and ferric ions (Fe). N and Fe, not only adjust the band structure of CN through quantum confinement effect and the altered coupled oscillations of atomic orbitals to facilitates •OH production by oxidizing OH, but also construct dual carrier-transfer channels for electrons and holes to respective active sites by introducing stepped electrostatic potential and shortening three-electron bonds, thereby involving more carriers in •OH production. Fe/N-CN, the novel reactor, effectually produces vast •OH under illumination by expanding OH as the raw material of •OH and augmenting carriers at active sites, which induces cancer cell apoptosis by disrupting mitochondrial function for significant shrinkage of Cal27 cell-induced tumor under illumination. This work provides not only an effective photosensitizer avoiding the accumulation of OH for cancer therapy but also a novel strategy by constructing dual carrier-transfer channels on semiconductor photosensitizers for improving the therapeutic effect of photodynamic therapy.