Scintillator-Based Nanohybrids with Sacrificial Electron Prodrug for Enhanced X-ray-Induced Photodynamic Therapy.

X-ray-induced photodynamic therapy (X-PDT) has high depth of penetration and has considerable potential for applications in cancer therapy. Scintillators and heavy metals have been adopted to absorb X-rays and transmit the energy to photosensitizers. However, the low efficiency of converting X-rays to reactive oxygen species (ROS) presents a challenge for the use of X-PDT to cure cancer. In this study, a new method based on LiLuF4:Ce@SiO2@Ag3PO4@Pt(IV) nanoparticles (LAPNP) is presented that could be used to enhance the curative effects of X-PDT. To make full use of the fluorescence produced by nanoscintillators (LiLuF4:Ce), a cisplatin prodrug Pt(IV) was utilized as a sacrificial electron acceptor to increase the yield of hydroxyl radicals (·OH) by increasing the separation of electrons and holes in photosensitizers (Ag3PO4). Additionally, cisplatin is produced upon the acceptance of electrons by Pt(IV) and further enhances the damage caused by ·OH. Via two-step amplification, the potential of LAPNP to enhance the effects of X-PDT has been demonstrated.