The membrane-mediated interaction between nano-objects
| When |
Oct 06, 2015
from 10:45 to 12:00 |
|---|---|
| Where | Centre Blaise Pascal |
| Attendees |
Doru Constantin |
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We probe the interaction induced by lipid membranes between included molecules and other nano-objects. This study presents both a fundamental interest, from the point of view of soft matter physics, and a relevance to understanding the activity of important biological molecules, such as native membrane proteins and antimicrobial peptides. In particular, the cytotoxic activity of the latter is directly related to the composition of the membrane (charge, thickness, presence of cholesterol) rather than to specific chemical recognition. It has long been posited that highly simplified descriptions (e.g. in terms of "hydrophobic matching") capture the essence of the process, but the extensive body of theoretical and numerical work cannot be validated and refined due to the lack of experimental results.
Using small-angle X-ray scattering, we study highly aligned lipid multilayers, doped with antimicrobial peptides and hybrid nanoparticles. The resulting two-dimensional structure factor of the fluid formed by the inclusions yields the interaction potential in the plane of the membrane. We compare this potential to the predictions of a recent theoretical model and show that good agreement can be reached for particular anchoring conditions. We also consider the role of interactions between particles in neighbouring membranes and their experimental detection.
The long-term goal of this investigation is a clearer picture of the lipid membrane as a complex two-dimensional fluid and of the way it influences the interaction between included objects, in particular antimicrobial peptides and membrane proteins.