|Место работы (учебы):
University of Milan, Italy
|Должность (курс обучения):
Modeling interactions at membrane surface: structural insights obtained by neutron reflection
Biomembranes are complex objects made by several different molecular species. One of their most significant complexities is compositional asymmetry. Regions exist where asymmetry, both lateral and transverse, is a key factor, as in glycosphingolipids enriched rafts, where the uneven disposition is claimed to be associated to functional and structural roles. Nonetheless, membranes asymmetry is often an underestimated feature and hard to reproduce in mimics. Experimental models, bearing forced membrane leaflets asymmetry in the form of disperse aggregates in solution or of single supported bilayers, have been developed to be suitably investigated by light, neutron and x-ray scattering and reflectivity. Neutron reflectometry allowed to access the cross structure of raft-mimes, assessing that the presence of a typical raft glycosphingolipid, GM1 ganglioside, forces asymmetry in cholesterol distribution, proving that a true coupling between the two molecules occurs. Similar investigations on animals and plant mimics revealed that the degree of sterols asymmetry depends on the specific membrane domain under study.
Another complexity which may be reproduced in mimics is the presence of mucus layers covering several body tracts. Mucus, an hydrogel mainly composed by mucin, acts as selective barrier for incoming molecules and microorganisms. Neutron reflectometry allowed to develop and structurally investigate a bio-inspired complex model system consisting in a mucin layer deposited on top of a single supported model membrane.
Membranes selectivity depends on both the local structure and the specific composition. Multitechnique investigations allowed to address the structural response of model membranes to approaching polymers, enzymes, and proteins such as Alpha-Synuclein, Aβ peptides and ion channel proteins.
The possibility to create and study customized membranes mimicking different membrane portions opens the way to the detailed investigation of a variety of specific molecule-membrane interactions, to be potentially predictive of the fate of macromolecules, such as nanodrugs intended to reach membrane surface, eventually after crossing the mucus barrier. In this perspective neutron reflectometry is a powerful tool, allowing the cross-structural investigation of complex biosystems with few Angstrom sensitivity.
Researcher at the Medical Biotechnologies and Translational Medicine Department of the University of Milano, Italy.
Valeria Rondelli is an experimental biophysicist with a multidisciplinary background. Her interest falls in the investigation of the self-assembly and structuring of biomacromolecules and pharmaceutical nanovectors in solution.
In particular she is interested in the development and structural description of complex models for biomembranes and tissues, suitable to be investigated by techniques such as neutron and X-ray scattering and reflectometry.
She exploited the complex models built-up and characterized, to perform detailed investigations on membrane interaction with several biomolecules, such as surfactants, proteins, peptides, enzymes.
She is well known as expert user and collaborator for experimental environments development in the European Large Scale Facilities for X-rays and neutron research.
2008 Master Degree in Physics, Università degli Studi di Milano, Italy
2008 Fellow, Institute of Pharmacological Research ‘Mario Negri’, Milano, Italy
2009 –2011 Long Term Visitor, Institute Laue-Langevin (ILL), France
2012 Ph.D in Biochemistry, Università degli Studi di Milano, Italy
2012 –2016 Post-Doc in Physics, Università degli Studi di Milano, Italy
2016 — present Steering committee of the Italian Society of Pure and Applied Biophysics
Present Researcher in Applied Physics, Università degli Studi di Milano, Italy