Poly(glycerol)-Functionalized Gadolinium Tungstate Nanoflakes Loaded with Chlorin e6: Photodynamic Efficacy and Radiosensitization Potential for Multimodal Cancer Therapy

Gadolinium (Gd)-based nanomaterials have attracted a considerable amount of attention in cancer treatment research due to their applicability in radiotherapy. However, the clinical translation of Gd-based nanomaterials is limited by their high density and poor dispersibility in aqueous media, thereby necessitating surface functionalization with biocompatible polymers. In this study, gadolinium tungstate (Gd₂(WO₄)₃) nanoflakes (GW Nfs) were functionalized with poly(glycerol) (PG) to enhance their dispersibility and stability in aqueous media. Due to their high-<i>Z</i> elemental composition, the GW Nfs generated reactive oxygen species (ROS) under X-ray irradiation, with improved dispersibility induced by PG functionalization further enhancing ROS productivity compared to GW Nfs. Furthermore, PG-GW loaded with the photosensitizer chlorin e6 (Ce6) demonstrated strong photocytotoxicity at Ce6 concentrations as low as 0.2 μg mL^-1 under light irradiation. Taken together, these results demonstrate that PG-GW/Ce6 is a promising nanomaterial for photodynamic therapy while also offering prospects for bimodal photon cancer therapy with X-rays.