Fabrication, characterization, and radiosensitization effect of platinum nanoparticles on globlastoma U87 cells

Abstract

Glioblastoma (GBM) is an aggressive and radioresistant brain tumor with limited response to conventional radiation therapy (RT). High atomic number (high-Z) nanoparticles have emerged as promising radiosensitizers due to their ability to enhance radiation-induced reactive oxygen species (ROS) generation and DNA damage. In this study, platinum nanoparticles (Pt-NPs) were synthesized and evaluated for their radiosensitizing effects in U87 glioblastoma cells. Physicochemical characterization revealed that Pt-NPs exhibited a spherical morphology with a spiky surface, a hydrodynamic diameter of 121 ± 13 nm, and a highly negative zeta potential (−42 ± 1.4 mV), indicating good colloidal stability. Cytotoxicity was assessed using the MTT assay, which demonstrated a concentration-dependent decrease in cell viability, and an IC₁₀ of approximately 55 µg/mL was selected for subsequent experiments to minimize intrinsic nanoparticle toxicity. Clonogenic survival assays showed that Pt-NPs combined with 2 Gy irradiation significantly reduced the surviving fraction compared with Pt-NPs or irradiation alone, yielding a sensitizer enhancement ratio (SER) of 2.66. Consistently, increased γ-H2AX expression and intracellular ROS levels were observed following combined treatment, indicating enhanced DNA double-strand break formation. Furthermore, Pt-NPs in combination with irradiation induced cell cycle perturbation and increased apoptotic cell death. These findings demonstrate that Pt-NPs effectively improve the radiosensitivity of U87 glioblastoma cells through ROSmediated DNA damage and apoptosis, highlighting their potential as nanomaterialbased radiosensitizers for glioblastoma radiation therapy.