Rare earth-doped nanomaterials: Tuning photophysical properties for enhanced photodynamic and photothermal therapy

As human lifespan increases with societal development, tumors have become one of the major diseases threatening public health. However, traditional cancer therapies face inevitable limitations and side effects. Consequently, minimally invasive alternatives, such as photodynamic therapy (PDT) and photothermal therapy (PTT), have attracted significant research interest. This comprehensive review summarizes the application of rare-earth-doped and rare-earth-containing nanomaterials in PDT and PTT for cancer therapy. We first introduce the fundamental principles of both therapies and the critical role of rare earth (RE) components, followed by a discussion of four major material categories: carbon-based nanomaterials, upconversion nanomaterials, sulfide/oxide nanoparticles, and metal nanocomposites. Furthermore, the review discusses the phototherapeutic applications of these materials from a mechanism-guided perspective, with emphasis on PDT, PTT, and synergistic combined therapy. Finally, we address the current challenges, proposed solutions, and future prospects of this rapidly developing field. Rather than functioning as universal performance enhancers, RE components regulate phototherapy through ion-specific mechanisms, including Near-infrared (NIR)-to-visible/Ultraviolet (UV) conversion, photosensitizer activation, oxygen/reactive oxygen species modulation, magnetic or optical imaging, and temperature-feedback monitoring. These multifunctional roles provide a promising but still preclinical foundation for next-generation tumor phototherapy, provided that biosafety, irradiation parameters, metabolism, and scalable synthesis are carefully evaluated.