Analysis of the excited state and DNA interactions of ruthenium-phthalocyanine complexes with potential application in X-ray-induced photodynamic therapy

• Grant number: 25/09172-6
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: December 01, 2025
• End date: May 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Inorganic Chemistry
• Principal Investigator: Roberto Santana da Silva
• Grantee: Eduardo Rodrigues da Silva
• Supervisor: Claudia Turro
• Host Institution: Faculdade de Ciências Farmacêuticas de Ribeirão Preto (FCFRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Institution abroad: Ohio State University, United States
• Associated to the scholarship: 24/06347-7 - X-Ray Induced photodynamic therapy using ruthenium complexes as nitric oxide and singlet oxygen generating agents: chemical, photochemical, and biological studies in tumor and Non-tumor cells, BP.MS

Abstract

Cancer continues to be one of the greatest global health challenges due to uncontrolled cell proliferation and metastasis. Traditional treatments face limitations such as toxicity, resistance, and low selectivity. In this context, alternative therapies such as photodynamic therapy (PDT) have stood out. PDT uses a photosensitizer (Ps) activated by light to generate cytotoxic species and induce cell death. To overcome the low penetration of visible light, X-ray-induced photodynamic therapy (X-PDT) uses ionizing radiation and scintillating nanoparticles that emit energy in a specific region, which the Ps absorbs to initiate the entire photodynamic process, enabling the treatment of deeper tissues. Phthalocyanines, especially when coordinated with metals like ruthenium, stand out as photosensitizers due to their conjugated structure and favorable chemical properties. Ruthenium facilitates the transition to the triplet excited state, which is essential for Type I and II reactions that generate reactive oxygen species (ROS), such as singlet oxygen. Furthermore, these molecules can interact with DNA, promoting selective damage to tumor cells through electrostatic, covalent, or intercalative interactions. Therefore, this project aims to study the excited states of the complexes [RuPc(4-pic)2], (nBu4N)2 [RuPc(NO2)2], and [RuPc(NO)(ONO)], exploring their efficiency in ROS generation for future application in X-PDT, as well as their interaction with DNA. (AU)