Welcome to the monthly Joint ESS-MAX IV Science Colloquium!
Structure and fluctuations of model membranes: complementarity of neutron and synchrotron radiation methods
The understanding of the function of cellular membranes requires the study of their structure and dynamics. Cellular membranes are complex assemblies of lipids and proteins. In particular the lipid scaffold, is composed by a large variety of lipid species and levels of chain unsaturation, often difficult to synthesise chemically. Because of this complexity, model membrane systems from simple lipid bilayers are often used for fundamental studies and those can profit from probes able to access different scales of size and time like thermal neutrons and synchrotron radiation. Since the pioneering neutron scattering work in the seventies on cell membrane structure, developments driven by constantly improving neutron instrumentation, coupled with development of measurement and analysis methods, have involved both the optimisation of samples towards more biologically relevant model systems including the use of more and more complex lipid mixtures up to natural extracts.
Here, we will focus on the complementarity of neutron and synchrotron radiation for the study of the structure and fluctuations of model membrane systems, using recent examples from the study of the out-of-equilibrium fluctuations of phospholipid membranes induced by the active transmembrane protein bacteriorhodopsin [Mukhina et al., JCIS (2021)] and the study of the attractive interaction between fully charged lipid bilayers in a strongly-confined geometry [J. Phys. Chem. Lett. 2019].
The importance of sample preparation and sample environment will be highlighted as well as synergies made possible by co-location of large facilities like ILL and ESRF in Grenoble that can be used as example in Lund by ESS and MAX-IV.