Activation et Guidage par Irradiation X nanoparticle (AGuIX)

AGuIX (Activation et Guidage par Irradiation X) is a sub-5 nm theranostic nanoparticle composed of a polysiloxane core with covalently grafted gadolinium chelates (MDPI, 2025; NIH, 2024). It is designed to accumulate in tumors via the enhanced permeability and retention (EPR) effect and is primarily used as a radiosensitizer and MRI contrast agent (MDPI, 2021; NIH, 2023). Upon exposure to ionizing radiation, the high-atomic-number gadolinium atoms within the nanoparticle emit secondary electrons, such as photoelectrons and Auger electrons, which locally amplify the radiation dose and generate reactive oxygen species (ROS) (ACS, 2020; MDPI, 2025). This process leads to increased DNA damage, including double-strand breaks, and subsequent tumor cell death through mechanisms like apoptosis and ferroptosis (ACS, 2020; MDPI, 2025). Additionally, the paramagnetic properties of gadolinium allow for real-time monitoring of the nanoparticle's distribution and tumor accumulation via T1-weighted MRI (NIH, 2024). AGuIX is currently being evaluated in multiple clinical trials for indications such as brain metastases, glioblastoma, and lung cancer, demonstrating a favorable safety profile with rapid renal clearance (NIH, 2023; NIH, 2024).

Other names

Gadolinium-based nanoparticleAGuIX-GdPolysiloxane-gadolinium nanoparticleTheranostic nanoparticle

AGuIX acts as a radiosensitizer by utilizing the high-Z element gadolinium to enhance the local deposition of radiation energy through the emission of photoelectrons and Auger electrons, leading to increased production of reactive oxygen species and DNA damage. It also functions as a T1-weighted MRI contrast agent due to the paramagnetic properties of the gadolinium chelates.