On January 12-14 the meeting BILL2011-Bilayers at the ILL (www.ill.eu/news-events/events/bill2011/) took place at the Institut Laue-Langevin in Grenoble. The meeting gathered scientists whose interest was to apply neutron methods to lipid bilayer systems. More than 80 scientists (including 25 students) mainly from Europe but also from North America and Australia attended with 29 invited and contributed talks.

The last decades have seen a great bloom in the study lipid bilayers as it has become clear that elucidating the physical properties of lipids is essential to understand the functioning of living cells in both health and disease. Scattering techniques are today recognized as powerful tools for the characterization of biological membranes and tremendous progress has been made in the structure and dynamics of bio-mimetic systems in recent years.   At the same time, scattering experiments have evolved to address new model systems that better mimic cell membranes by incorporation of specific molecules such as peptides and membrane proteins, components of the cytoskeleton and the glycocalix, as well as skin lipids and myelin components.

The aim of this workshop was to continue the discussion on model membranes initiated at the ISIS Bilayers 2009 meeting by reviewing current neutron scattering work on lipid bilayer structure and its relevance to biomedical applications, followed by discussions on current and new methods to obtain stable, reproducible, and biologically relevant model membranes, optimization of sample environments, data-analysis, and the applications of emerging scattering techniques.

The meeting was opened with a short overview of the ILL facilities including both the instrumentation used for lipid bilayer studies and the support laboratories present on site to enhance the impact of science in the field. ILL Senior Fellow in Biology Joe Zaccai followed and guided the audience through a neutron trip from bilayers to moving membranes. He showed how elegant neutron scattering experiments on the dynamic coupling between the membrane protein Bacteriorhodopsin, water and the lipids were essential to understand the purple membrane activity. The first plenary speaker, Don Engelman from Yale (US), presented a review of several years’ work in his lab on the interaction of membrane-penetrating peptides with lipids and their recent exciting use in targeting tumors. A session on Membrane Structure and Self-Assembly followed that featured John Katsaras from Oak Ridge (US) in a very entertaining presentation on the functional significance of lipid diversity showing new results on how the still controversial orientation of cholesterol and domain formation in bilayers is determined by lipid species. The day concluded with aperitifs around a lively poster session. More than 30 posters on display presented a variety studies of bilayer systems further proving the richness of work carried out in the area of biological membranes.

Patricia Bassereau from Institut Curie (Paris) started the second day with a plenary talk on membrane trafficking in the Current Challenges section. After this non-neutron talk in which Patricia provided inspiring examples for neutron scatterers of relevant biophysical problems, Tonya Kuhl from UC Davis (US) showed both neutron and x-ray data from a promising polymer cushioned membrane system. In the afternoon session on Emerging Techniques Maikel Rheinstädter, McMaster (CA), presented exciting results on the dynamics of lipid rafts as probed by pushing the limits of inelastic neutron scattering techniques and the EBSA (European Biophysical Societies’ Association) sponsored speaker Emanuel Schneck, TU München (DE), described the influence of membrane-bound saccharides on the mechanical properties of interacting membranes as studied by specular and off-specular neutron scattering. In the Structural Analysis of Membranes session Thomas Hauß from HZB (DE) talked about the importance of combining structural and dynamical data from the interaction of Amyloid-b peptides with membranes in the search for a cure to Alhzeimer disease. The Lateral Structure session featured talks by Thierry Charitat from ICS Strasbourg (F) and Jaroslaw Majewski from Los Alamos (US) on the impressive developments of synchrotron radiation studies on the structure and fluctuations of lipid bilayers.

A lively Round Table took place at the end of the day before the social dinner.

The discussion concentrated mostly on the grand challenges in the field and ways to acquire visibility within the biological/biomedical communities. Concerns were expressed that the impact of structural studies on lipid bilayers in biology is limited and facilities should concentrate on ways to improve this situation. It was agreed that the keywords to success are impact and production. Scientific leadership is needed inside the neutron facilities to give direction to the labs and people (PhDs, post-docs) to produce science and to participate to relevant meetings outside the neutron community to increase the visibility of neutron scattering. It was also agreed that, in order to succeed, we need to tell a Good Story to attract users as well as funders.  It would be most efficient to select small well-defined problems with big impact (i.e. effect of cholesterol for diseases) and make a collective effort to work on them, instead of trying to compete in high visibility fields such as membrane protein structural biology, in which the crystallographic community enjoys the advantages of resolution and throughput. To aid in the selection of suitable flag-ship projects, existing networks of scientists in biology and biomedical fields should be sought out.

One important issue that was raised was that timescales of neutron experiments (from the proposal submission to data analysis) compared to times of research in biology in general are much too long. Therefore, it is of utmost importance to concentrate on solving problems that cannot be solved by any other techniques. When collaborating with external users facility experts need to think of the scientific issues explored and not the technical aspects. Many of the systems of interest are not well-characterised, and it may be difficult to adapt them to neutron experiments. Thus it is essential to ask the right questions as well as to simplify them, because biologists want to understand a particular biological process and often do not need to analyse the full structure of the experimental system that we as physical scientists are used to seeking.

Current big challenges that can be tackled by neutron techniques include the dynamics of lipid domains (processes are incredibly fast, timescales not known), biomedical engineering (interaction of surfaces with biological materials), and complex systems.

The last part of the round table was devoted to a discussion on the deuterated lipid extraction facility that the ILL is setting up within the Partnership for Soft Condensed Matter in collaboration with the D-Lab, which is capable of providing deuterated biomass on large scale.

On friday morning the session on Biological Applications was opened by Laura Cantú from Milano (I) who gave a very well-received presentation on the role of lipid domains formed by complex gangliosides and cholesterol. The final session of the meeting on Applications of Membranes featured a talk by Donald Martin from the UT Sydney (AUS) on the use of tethered membranes for bio-technology. He pointed out how a deeper understanding of these systems is needed to optimize the practical devices and how important it is to learn lessons from Nature, such as how grizzly bears use a flow system (i.e. rapids) to catch fish more efficiently. 

The chairman of the last session, Tommy Nylander from Lund announced that next meeting will be co-hosted with ESS in 2012-2013.

Overall the workshop was very successful and provided a great forum of exchange both for “old friends” and newcomers in the field. As a result, a number of collaborations among different laboratories have already started.

The organizers wish to thank all the participants for making the meeting a great success and acknowledge financial support from ILL, ESS, Biolin Scientific, EBSA and Avanti Polar Lipids.