Design of theranostic agents based on upconversion nanoparticles with core-multi-shell architectures of LiREF4 doped with lanthanides(III) and grafted with luminescent iridium(III) complexes

• Grant number: 24/21506-4
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: April 01, 2025
• End date: November 30, 2025
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
• Principal Investigator: Sergio Antonio Marques de Lima
• Grantee: Renan Caike Silva
• Supervisor: Fiorenzo Vetrone
• Host Institution: Faculdade de Ciências e Tecnologia (FCT). Universidade Estadual Paulista (UNESP). Campus de Presidente Prudente. Presidente Prudente , SP, Brazil
• Institution abroad: Institut National de la Recherche Scientifique (INRS), Canada
• Associated to the scholarship: 22/14042-6 - Multifunctional Up-conversion Luminescent Platforms Based on LiYF4:Tm3+,Yb3+@SiO2 nanoparticles decorated with iridium(III) complexes as agents in sensing and photodynamic therapy, BP.DR

Abstract

Rare-earth ions (RE3+) doped upconversion nanoparticles (UCNPs) are promising materials with great potential for applications in nanomedicine. They can be designed as a core-shell layered architecture that allows for the adjustment of their physicochemical and biological properties, facilitating the development of multifunctional luminescent nanoplatforms as theranostic agents. These UCNPs can perform theranostic functions by integrating diagnosis and treatment into a single nanoplatform. UCNPs emerge as a solution to overcome the limitation of UV excitation present in some theranostic agents, which reduces efficiency due to low light penetration in tissues and the toxicity of this energy range to biological systems. The use of near-infrared (NIR) excitation sources, especially between 700 and 1000 nm (BW-I), enables deeper tissue penetration and reduces autofluorescence and phototoxicity effects. In this context, the candidate aims to develop part of his PhD project (FAPESP: 2022/14042-6) during his BEPE fellowship, with the goal of synthesizing and studying the spectroscopic properties and theranostic viability of core-multi-shell UCNPs based on LiREF4 (RE3+: Y3+/Lu3+/Yb3+), co-doped with sensitizer ions Yb3+/Nd3+ and doped with activator ions Tm3+/Er3+/Ho3+. The UCNPs will be coated with silica, amino-functionalized, and finally decorated with luminescent iridium(III) complexes. This nanoplatform, LiREF4/SiO2-NC-[(L)Ir(C^N)2], will be capable of converting excitation at 980 nm (Yb3+) or at 808 nm (Nd3+) into emissions in the UV-blue-green region from Tm3+/Er3+/Ho3+ ions, resonating with the absorption of Ir3+ complexes. The UCNPs will act as sensitizers for the Ir3+ complexes on the surface, triggering predominantly triplet 3LC-1,3MLCT emissions, with the capability for oxygen sensing and reactive oxygen species generation. Thus, the project aims to develop a multifunctional luminescent nanoplatform with core-multi-shell LiREF4 UCNPs decorated with Ir3+ complexes for applications in sensing, bioconjugation to specific cellular targets for cellular imaging, and photodynamic therapy