New photosensitizers obtained from selenilation of methyl pheophorbide a and curcumin: applications in PDT and photodiagnosis

• Grant number: 21/01259-4
• Support type: Scholarships in Brazil - Post-Doctorate
• Effective date (Start): May 01, 2021
• Effective date (End): June 30, 2022
• Field of knowledge: Physical Sciences and Mathematics - Physics
• Principal researcher: Vanderlei Salvador Bagnato
• Grantee: Guilherme Ariel Machado Martins
• Home Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 13/07276-1 - CEPOF - Optics and Photonic Research Center, AP.CEPID

Abstract

Photodynamic therapy has been used for microbial control and local treatment of superficial injuries with promising results. Limitations are found in both applications, and one of the effective strategies is the development of new photosensitizers that are more appropriate and efficient for each application. The main objective of this study is to synthesize, characterize and evaluate the efficiency of new photosensitizers containing selenium for use in photodynamic therapy studies. The evaluation of photodynamic efficiency will be based on the production of reactive species and the action on biological systems. The present study has the potential to improve the understanding of the influence of chemical structure on biological action and the indication of the most suitable photosensitizer for the cell types to be investigated. Furthermore, the proposed photosensitizers have the potential to act both in the production of reactive oxygen species and in the diagnosis by fluorescence at different wavelengths, the latter application being one of the major bets for innovation in this project. We believe that the selenium atoms linked to the PS core can be oxidized in situ, allowing a mechanism of on/off activation of fluorescence in different emission regions.The chemical syntheses will be developed in the laboratory of Prof. Kleber de Oliveira/UFSCar, involving the extraction and purification of chlorophyll from maximum Spirulina, followed by obtaining the methyl-phoroforbide a, which will serve as starting material for a series of semi-syntheses and functionalizations with selenium. We will also carry out the synthesis of curcumin, as well as some functionalization reactions with aryl-selenium derivatives following a similar purpose of modulating the photophysical properties of curcumin as well as prospecting it for use in fluorescence diagnosis. (AU)