Lipid photo-oxidation mediated by the xanthene Rose Bengal in healthy and tumor cell model systems based on Lamgmuir films

• Grant number: 19/03650-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2019
• End date: October 31, 2021
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Pedro Henrique Benites Aoki
• Grantee: Bryan Lucas Alfenas Borges
• Host Institution: Faculdade de Ciências e Letras (FCL-ASSIS). Universidade Estadual Paulista (UNESP). Campus de Assis. Assis , SP, Brazil
• Associated scholarship(s): 19/20897-1 - On the photoinduced modifications of giant unilamellar vesicles containing rose bengal, BE.EP.IC

Abstract

The photodynamic therapy (PDT) is an emerging therapeutic modality, clinically approved and minimally invasive, which has called great attention for the treatment of carcinomas. The method is based on the controlled administration of a photosensitizer (PS), which induces the singlet oxygen (1O2) formation, an oxidizing agent capable of causing necrosis or apoptosis in cancer cells. It is known that cell membranes and especially unsaturated phospholipids are the major targets of 1O2. However, the molecular level mechanism underlying the effects of photoinduced oxidation over self-assembled phospholipid structures are not yet completely understood. Herein, we shall use Langmuir monolayers of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-dioleoyl-snglycero-3-phosphocholine (DOPC) and 1,2-dioleoyl- glycero-3-phospho-L-serine (DOPS) as cell membrane models to investigate the interaction of rose bengal (RB) PS and the effects of photoinduced lipid oxidation. RB belongs to the xanthene family and presents high quantum yield in 1O2 generation. Langmuir monolayers will be prepared on ultrapure water subphase and different concentrations of RB (10-4, 10-5 e 10-6 mol/L), characterized by surface pressure vs mean molecular area (À-A isotherms) measurements. After the incorporation of RB by the membrane, the PS will be photoactivated to evaluate the effects of lipid oxidation on the physicochemical properties of the membrane, which include the increase of the mean molecular area occupied by the lipids and the cleavage of the carbon chains. This Scientific Initiation project is conceived within the FAPESP Regular Grant (2018/16713-0) under development with the FCL/UNESP Biotechnology Department.