With the recent advances in neutron sources and instrumentation, and the start-up of ESS, there is an urgent need for deuterating complex molecular architectures for studying a range of advanced materials with neutron scattering.
DEUNET will address the issue by developing:
• A cost-effective platform to provide access to a broad range of materials and expertise
• New synthetic methods and products
• Synthesis of innovative materials in collaboration with partners
• Coordinated service for European neutron users
Task 2. Extraction and purification of small molecules from deuterated cell cultures
Task leader: ILL
We will set-up, in the framework of the Partnership for Soft Condensed Matter (PSCM), procedures for the separation, purification and analysis of small, deuterated biological molecules derived from cell cultures, which will complement the macromolecular deuteration capabilities. The main task will be to develop methods for the separation and purification of:
• Main amphiphilic lipid components of biological membranes
• Raft forming molecules such as gangliosides and cholesterol
SMSS personnel involved: Giovanna Fragneto, Rachel Morrison
- Röntgen-Ångström grant: A planar three‐phase interaction apparatus for neutron reflectometry
PIs: Emanuel Schneck, MPIKG and Fredrik Höök, Chalmers
PR: Yuri Gerelli, ILL
This project aims at the design and realization of a novel setup for the structural investigation of interacting soft interfaces using neutron reflectometry (NR). Once implemented, this setup will allow monitoring the structural changes associated with the interaction of biologically or technologically relevant surfaces across aqueous layers at defined, externally applied interaction pressures. We are mainly interested in the utilization of this setup for the study of the physical mechanisms involved in the generic and specific interactions of biological membranes. However the development of the setup and the expected first results may provide the basis for a multitude of future studies on membrane interactions but also on technologically motivated studies on polymer physics, colloidal interactions, and many more. The final design of the setup and our methodology will be made available also to other neutron sources.
SMSS personnel involved: Yuri Gerelli, Samantha Micciulla
- Effect of Pressure on the Soft-Matter Systems Accomplished by Ionic Assembly
PSCM Partnership Agreement
The main theme of the planned joint research will be on the effects of pressure on the assembly behaviour of various soft-matter systems. This has not been much studied yet, despite the fact of its importance for different fields of technological applications but also in biology. Furthermore substantial insights into the thermodynamic and kinetic fundamentals of self-assembly can be obtained from such studies. We will focus in our investigations on systems obtained by ionic assembly employing polyelectrolytes and surfactants. In such systems pronounced effects of electrostriction are expected and therefore corresponding effects on their aggregation behaviour as a function of pressure can be foreseen. For that purpose we will set out for a systematic investigation for different such oppositely charged systems that will first be studied by light scattering and then the most interesting ones by means of SANS/SAXS and NSE. Based on these experiments we will be able to lay out a correlation between the molecular build-up of the constituents and the effects of pressure on the corresponding complexes, as well as concerning the thermodynamical and structural effects seen there. In a later stage we then will apply this knowledge to study the kinetics of rearrangement in such systems (for instance by the TISANE method) as they can be induced by pressure jumps, which will give unique insights into the dynamics of such systems, but this information and the kinetic pathways are also highly relevant for designing such ionically assembled systems further. In summary this research will advance our understanding of ionically assembled systems substantially further and in particular allow to employ the parameter pressure as an important control parameter.
LSS and SMSS personnel involved: Ralf Schweins, Leonardo Chiappisi
- SANS on Functional Soft Matter Systems during Preparation and in Complex Environments
PI: Michael Gradzielski, TU Berlin
PR: Ralf Schweins, ILL
The aim of this project is to develop SANS sample environments for the investigation of functional soft matter systems under conditions relevant to their synthesis and in-operando performance. This will allow us to gain an understanding of the relationship between the properties and the mesoscopic structure of such materials and is therefore highly relevant across the field of soft matter, from polymer chemistry to life sciences. The sample environments will facilitate the study of materials: in electric fields, under capillary or Poiseuille Flow and during changes to the chemical environment. The latter will also include a number complementary measurement techniques providing continuous information on the pH, turbidity, conductivity and wavelength-dependent absorbance over the course of the experiment. Once completed, the sample environments will be commissioned with a range of experiments exploring polymerisation-induced self-assembly, guest-host liquid crystal systems and cylindrical micelles and will then be made available to users.
LSS and SMSS personnel involved: Ralf Schweins, Sylvain Prevost, Leonardo Chiappisi, Dominic Hayward
- Influence of the protein corona on the interaction between engineered nanoparticles and model membrane system
PhD project Loïc Joly (collaboration with F. Baldelli-Bombelli, University of Milan and M. Maccarini, TIMC Grenoble)
ILL supervisor: G. Fragneto
- Self-assembly of polyelectrolyte block copolymers and multivalentcations
Part of the PSCM partnership
PhD project Nico Carl (collaboration with K. Huber, University of Paderborn)
ILL supervisor: Ralf Schweins
Block copolymers of anionic polyelectrolytes can be self-assembled into micelles in the presence of multivalent cations such as Ca2+ or Ba2+. The project focuses on the structural characterization of such micelles and the thermodynamic fundamentals of the self-assembly process. For this small angle-neutron (SANS), X-ray (SAXS) and light scattering (DLS and SLS) are combined in order to obtain structural information. In addition, isothermal titration calorimetry (ITC) offers direct access to the thermodynamic parameters of the micelle formation.
The project aims towards a better understanding of the specific interaction of polyelectrolytes with oppositely charged species. Moreover, we aim to design novel responsive materials, which can be controlled by external stimuli such as pH, temperature, ionic strength or light.
- Out-of-equilibrium active membranes: detergent-mediated incorporation of proteins into phospholipids bilayers
PhD project Tetiana Mukhina (collaboration with Thierry Charitat, Strasbourg University)
ILL supervisors: G. Fragneto/Y. Gerelli
The main aim of this project is to investigate the non-equilibrium fluctuations of phospholipid membranes induced by light-activated transmembrane proteins, Bacteriorhodopsin and Archaerhodopsin-3. The first part of the project is focused on the development of the protocol to insert proteins, in their active state, into phospholipid bilayers such as: solid-supported bilayers, PEG-tethered and floating phospholipid bilayers. The second, and more important step of this work is to investigate the structural changes induced to the membrane by protein incorporation and activation. Neutron reflectometry combined with X-ray reflectometry and complementary lab-based techniques will be used to study the effects of protein incorporation. Out-of-equilibrium fluctuations induced by the protein activation will be probed by synchrotron radiation off-specular measurements, which will allow to measure the off-specular signal and provide information on the lateral structural correlations of the systems.
Andrea Lassenberger, Anne Martel
This project aims to synthesize and characterize silk fibroin based hydrogels that are interesting materials for cell culture, tissue engineering, drug delivery and for wound dressings.
The protein silk fibroin, derived from the cocoons of the silkworm, is particularly interesting for its exceptional mechanical properties paired with inherent biocompatibility and biodegradability. Silk fibroin forms a hydrogel by a conformational change from random coin to β-sheet and the mechanical properties of the gel can be tuned by the extend of β-sheet content.
To further improve the properties of fibroin hydrogels, we combine them with metal oxide nanoparticles or lipids to improve and modify the gelation time, mechanical properties and to introduce the possibility to modify the gels by an external stimulus, e.g. magnetic fields. This way we can design intelligent hydrogels that can change their structure upon an external trigger and that way e.g. change the release properties of incorporated drugs.
The structure and composition of these composite hydrogels is characterized by a variation of methods such as small angle neutron scattering and dynamic light scattering, rheometry, FT-IR and CD spectroscopy and complementary microscopy methods.