Eosin decyl ester binding and photo-oxidation effects on simplified models of bacterial membrane based on giant unilamellar vesicles

• Grant number: 19/20853-4
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: December 08, 2019
• End date: March 07, 2020
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Pedro Henrique Benites Aoki
• Grantee: Lucas Gontijo Moreira
• Supervisor: Carlos Manuel Venâncio Marques Serra
• Host Institution: Faculdade de Ciências e Letras (FCL-ASSIS). Universidade Estadual Paulista (UNESP). Campus de Assis. Assis , SP, Brazil
• Institution abroad: Institut Charles Sadron (ICS), France
• Associated to the scholarship: 18/13021-0 - Photo-oxidation of Langmuir films as mimetic systems of Escherichia coli membrane, BP.IC

Abstract

The photodynamic inactivation of microorganisms (PDIM) has received considerable attention due to the efficiency against the super-resistance of bacteria. The technique is based on the controlled administration of a photosensitizer (PS), subsequently photoactivated for the generation of reactive oxygen species (ROS), responsible for the inactivation of microorganisms. It is known that the unsaturated phospholipids present in cell membranes are the main targets of ROS. However, the mechanisms of interaction with PSs as well the effects of lipid oxidation over the membrane properties are not yet fully understood. In this project, giant unilamellar vesicles (GUVs) will be used to mimic the lipid membrane of Escherichia coli, an important pathogen that has acquired resistance to antibiotics. For this purpose, GUVs of the unsaturated phospholipids 1,2-dioleoyl-sn-glycero-3-phosphatidylethanolamine (DOPE), 1,2-dioleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DOPG) and cardiolipin (CLP) will be assembled containing different concentrations of eosin decyl ester (EosDec). The EosDec incorporated into the membrane will be further photoactivated in order to evaluate the effects of lipid oxidation on the physical-chemical properties of the membrane, which include the increase of the mean molecular area occupied by the lipids and membrane permeability. This BEPE proposal is part of the scientific initiation project (2018/13021-0) entitled "Photo-oxidation of Langmuir films as mimetic systems of Escherichia coli membrane", which has been carried out at the FCL-UNESP, Assis, Brazil. (AU)