Sonosensitizers based on carbon dots doped with metal ions

• Grant number: 25/04239-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2025
• End date: March 31, 2026
• Field of knowledge: Health Sciences - Pharmacy
• Principal Investigator: Renata Galvão de Lima
• Grantee: Samuel Braga Garcia
• Host Institution: Faculdade de Ciências Farmacêuticas de Ribeirão Preto (FCFRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Sonodynamic therapy (SDT) is a non-invasive method that can be used to treat neoplasms. Among the advantages of using ultrasound (US) therapies are the excellent ability to penetrate biological tissues, the ability to focus US beams on small areas and the non-absorption of sound by pigmented cells, such as melanoma. SDT is a therapy based on the interaction of US with a sonoactive drug called a sonosensitizer. The propagation of US in the tissue can trigger some phenomena, such as acoustic nucleation and cavitation, that is, the formation and oscillation of gas/vapor bubbles. In the presence of nanoparticles with semiconductor characteristics, the implosions of gas bubbles excite the electrons (e¿) in the valence band (VB) to the conduction band (BC), leaving a hole (h+) in the VB. The formed e¿/h+ pairs can be transferred to the surrounding O2 or H2O, producing ROS, including O2*¿ and HO*. The recombination of e¿/h+ pairs will also release energy and can excite O2 to 1O2. Considering the fluorescent semiconductor characteristics of carbon dots, this project aims to synthesize carbon dots from polymeric carbonaceous doped with metal ions, such as Fe3+ and Mn2+, evaluate the production of ROS via US induction, the neutralizing redox effects of glutathione by metal ions, as well as study the cell viability of normal and tumor cells.