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-Z 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.