Structural, photoluminescent, and biological evaluation of Eu-doped Y₂O₃ nanoparticles for cancer theranostics, multimodal imaging, and antibacterial applications.

This study presents the synthesis and biological evaluation of Eu-doped Y₂O₃ nanoparticles with a focus on their potential relevance to cancer-related applications. The nanoparticles were prepared by a precipitation method followed by calcination at 850 °C and structurally characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), FTIR, and Raman spectroscopy. XRD analysis confirmed a well-defined cubic Y₂O₃ structure (space group Ia3̅, No. 206).Photoluminescence properties were investigated using 349 nm pulsed Nd:YLF laser excitation as a spectroscopic characterization tool, revealing characteristic orange-red emission associated with Eu electronic transitions and high color purity (97%).In vitro biological studies were conducted using Hep3B human hepatocellular carcinoma cells. Cytotoxicity and clonogenic potential were evaluated via MTT and colony formation assays, respectively. The results showed that undoped Y₂O₃ exhibited good biocompatibility, whereas Eu-doped Y₂O₃ induced dose- and time-dependent cytotoxic effects with an IC₅₀ value of 400 μg/mL and significantly inhibited colony formation. Furthermore, RT-qPCR analysis demonstrated a notable downregulation of VEGF, FGF, IL-1β, and IL-6, indicating anti-angiogenic and anti-inflammatory responses. Antibacterial activity tests revealed no significant inhibitory effects, which may be attributed to limited particle diffusion and minimal ion release. These findings demonstrate that Eu-doped Y₂O₃ nanoparticles exhibit combined luminescent and biological characteristics, supporting their further investigation as biologically oriented luminescent nanomaterials. Future studies may explore surface modification strategies to enhance biological interactions and therapeutic efficiency.