Functionalization of graphene quantum dots and hybrid systems with rare earth-doped luminescent nanoparticles to enhance specificity in theranostic brain imaging.

• Grant number: 24/11046-6
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: February 01, 2025
• End date: January 31, 2028
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
• Principal Investigator: Rogéria Rocha Gonçalves
• Grantee: Luiza Araújo Gusmão
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated research grant: 21/08111-2 - Development of rare earth based light converters: luminescent markers, optical sensors, and amplifiers, AP.TEM

Abstract

This project proposes the functionalization of graphene quantum dots (GQDs) containing TR+3 ions through conjugation with a transferrin (Tf) molecule, intending to improve the theranostic fluorescent properties of these quantum dots for imaging diseases of the central nervous system, with a special focus on glioblastomas (GBM). Two different approaches are proposed: doping of graphene quantum dots (PQG) with Eu3+ and Er3+/Yb3+ and the preparation of a PQG-UCNPs hybrid system (UCNPs -luminescent upconversion rare earth fluoride nanoparticles). Doping with Er3+/Yb3+ ions is promising for shifting the absorption band of PQG and PQG-UCNPs to the red and near-infrared regions, which are lower energy wavelengths with high penetration power in human body tissues. In addition, the introduction of Tf into the PQG structure aims to optimize the functionality of this nanomaterial, giving it greater specificity by being compatible with Tf receptors that are both present in the endothelial junctions of the blood-brain barrier (BBB) and overexpressed in glioma tumor cells, such as GBM. The aim is to improve the effectiveness of PQG and PQG-UCNPs as a contrast agent in imaging techniques. This approach has the potential to offer significant advances in the early detection and monitoring of GBM, contributing to the development of more efficient therapeutic strategies in the field of medical neuroimaging in Brazil and worldwide.