Leveraging Radiation‐triggered Metal Prodrug Activation Through Nanosurface Energy Transfer for Directed Radio‐chemo‐immunotherapy.

Metal‐based drugs currently dominate the field of chemotherapeutic agents; however, achieving the controlled activation of metal prodrugs remains a substantial challenge. Here, we propose a universal strategy for the radiation‐triggered activation of metal prodrugs via nanosurface energy transfer (NSET). The core–shell nanoplatform (Ru‐GNC) is composed of gold nanoclusters (GNC) and ruthenium (Ru)‐containing organic–inorganic hybrid coatings. Upon X‐ray irradiation, chemotherapeutic Ru (II) complexes were released in a controlled manner through a unique NSET process involving the transfer of photoelectron energy from the radiation‐excited Ru‐GNCs to the Ru‐containing hybrid layer. In contrast to the traditional radiation‐triggered activation of prodrugs, such an NSET‐based system ensures that the reactive species in the tumor microenvironment are present in sufficient quantity and are not easily quenched. Additionally, ultrasmall Ru‐GNCs preferably target mitochondria and profoundly disrupt the respiratory chain upon irradiation, leading to radiosensitization by generating abundant reactive oxygen species. Consequently, Ru‐GNC‐directed radiochemotherapy induces immunogenic cell death, resulting in significant therapeutic outcomes when combined with the programmed cell death‐ligand 1 (PD−L1) checkpoint blockade. This NSET strategy represents a breakthrough in designing radiation‐triggered nanoplatforms for metal‐prodrug‐mediated cancer treatment in an efficient and controllable manner. [ABSTRACT FROM AUTHOR]