Structural characterization of aqueous dispersions of anionic lipids

• Grant number: 13/14296-9
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: October 01, 2013
• End date: August 31, 2017
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Maria Teresa Moura Lamy
• Grantee: Daniela Akiko Nomura
• Host Institution: Instituto de Física (IF). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated scholarship(s): 15/14695-6 - SAXS on the structural characterization of DMPG aqueous dispersions, BE.EP.DD

Abstract

This project is part of a comprehensive study about anionic lipid dispersions developed by the Biophysical Group of the IFUSP, in collaboration with several other groups, involving theoretical models and experiments. The aim of the project is the structural study of the anionic lipid dimyristoyl phosphatidylglycerol (DMPG) in in media of different ionic strengths, using different experimental techniques. There are several studies for DMPG at low ionic strength, but in the presence of buffer (ionic strength ~ 10 mM). However, a few studies suggest a very peculiar structure for DMPG aggregates in pure water. We intend to study these dispersions, and compare them with dispersions in buffer at low ionic strength. Hence, with DMPG dispersed in pure water the electrostatic repulsion between polar headgroups will be enhanced, as they will not be shielded by ions in solution, and it will be possible to study the relevance of that interaction in the structure of DMPG aggregates. For a better understanding of the interactions between the polar surface of the bilayer and hydrocarbon tails, we intend to study mixed lipid dispersions of DMPG with neutral lipids, and other anionic lipids, but with larger hydrocarbon chains, such as DPPG (dipalmitoyl phosphatidylglycerol). Static and dynamic light scattering will be used to monitor the dimensions and form of the aggregates, and their interactions. Differential Scanning Calorimetry (DSC) should detect possible phase transitions, and with Small Angle X-ray Scattering (SAXS) and the Electron Spin Resonance (ESR) of spin labels incorporated into the aggregates it will be possible to get information about the molecular structure of the lipid aggregate. (AU)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

NOMURA, Daniela Akiko. Structural characterization of aqueous dispersions of anionic lipids. 2018. Doctoral Thesis - Universidade de São Paulo (USP). Instituto de Física (IF/SBI) São Paulo.