On the photoinduced modifications of giant unilamellar vesicles containing rose bengal

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 underlying effects of photoinduced oxidation over self-assembled phospholipid structures are not yet completely understood. Herein, we shall use giant unilamellar vesicles (GUVs) of 1,2-dioleoyl-sn-glycero-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. GUVs will be prepared using Gel-Assisted Formation method and exposed to different concentrations of RB characterized by optical microscopies. After the incorporation of RB, the PS will be photoactivated to evaluate the effects of lipid oxidation on the physicochemical properties of the membrane, which may include the increase of the mean molecular area occupied by the lipids and pore opening. This BEPE proposal is part of the scientific initiation project (2019/03650-2) entitled "Lipid photo-oxidation mediated by the xanthene Rose Bengal in healthy and tumor cell model systems based on Langmuir films", which has been carried out at the FCL-UNESP, Assis. (AU)