Self-assembly of biomacromolecular systems and its implications: protein physical gelation in organic-aqueous media and nanoemulsions stabilised by amphiphylic proteins

• Grant number: 09/14823-3
• Support Opportunities: Regular Research Grants
• Start date: December 01, 2009
• End date: November 30, 2011
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Elizabeth Pinheiro Gomes Arêas
• Grantee: Elizabeth Pinheiro Gomes Arêas
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

This project is concerned with the investigation of events of aggregation and self-assembly involving proteins in organic-aqueous media. The interest in that kind of phenomenology is justified by the relevance of its occurrence in several contexts of fundamental and applied science. Segregation in microenvironments constitutes in many cases the basic condition for the evolution of distinct functionalities in complex systems. The "dual" character of organic-aqueous liquid mixtures and the consequent microheterogeneity may constitute the driving force of many events of self-assembly, which are so relevant in Chemistry and Biology, both in terms of the organization of living systems and to the development of new materials. From another point of view, several pathologies, mainly of neurodegenerative character, have their origin in the protein capacity to aggregate, forming plaques that affect the normal functions of the regions where they are located. Despite relevant progress in the area, our present knowledge about the reasons that make proteins lose their original folding under certain conditions and evolve to disfunctional associated forms is still clearly insufficient. In particular, the role of the solvent media, more specifically in what concerns physico-chemical changes involved, is not properly understood. In this project, we intend to approach two kinds of phenomena involving globular protein self-assembly in aqueous-organic media: a) physical gelation of globular proteins induced by the solvent media; b) emulsification involving amphyphylic proteins, with particular interest in the conditions that may lead to the generation of nanoemulsions. (AU)