Theranostic Nanodevices: Exploring the viability of clinical contrast agents for X-ray Photodynamic Therapy

• Grant number: 25/01900-2
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: September 01, 2025
• End date: January 31, 2030
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Éder José Guidelli
• Grantee: João Victor Vieira Lessa
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated research grant: 24/21657-2 - From Oxygen to X-Rays: Different Nanotechnology Approaches for Cancer Treatment, AP.R

Abstract

This research project explores the development of barium sulfate (BaSO¿) nanoparticles doped with europium (Eu) and co-doped/functionalized with gadolinium (Gd)/Gd-chelated for application in X-ray Photodynamic Therapy (X-PDT), an innovative approach to the treatment of solid tumors. BaSO , already widely used as a radiological contrast agent due to its biocompatibility and high atomic number, has unique properties at the nanometer scale, such as greater colloidal stability and potential functionalization for therapeutic purposes. The X-PDT technique combines the benefits of conventional radiotherapy with the generation of reactive oxygen species (ROS) by the interaction of light emitted by the scintillating nanoparticles with conjugated photosensitizers, such as porfirins. This mechanism aims to intensify the localized damage to tumor tissue, maximizing therapeutic efficiency and minimizing adverse effects on healthy tissues. Doping with europium confers scintillating properties to nanoparticles, allowing the emission of light when exposed to ionizing radiation. The co-doping/fuction with Gd/Gd-chelated may also allow its use as a contrast agent in nuclear magnetic resonance (MRI) images, constituting a nanodevice theranostic. In this project, the synthesis, characterization and functionalization of these nanoparticles will be carried out, investigated the mechanisms of energy transfer from the nanocintholder to the photosensitizer, well, as verified the capabilities to produce ROS by exposure to x-rays and to act as contrast in MRI. Finally, cytotoxicity tests and clonogenic assays will be performed to verify if the production of ROS is sufficient to reduce the viability of cancer cells.