Structural characterization of aqueous dispersions of anionic lipids: dimyristoyl phosphatidylglycerol (DMPG) in water

• Grant number: 11/14507-4
• Support Opportunities: Scholarships in Brazil - Master
• Start date: March 01, 2012
• End date: September 30, 2013
• 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

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. It is part of the FAPESP project 2009/53074-6. The aim of the Project is the structural study of the anionic lipid dimyristoyl phosphatidylglycerol (DMPG) in pure water dispersions, 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 with electron microscopy suggest a very peculiar structure for DMPG aggregates in pure water. 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 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. 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.