A high pressure cell using metallic windows to investigate the structure of molecular solutions up to 600 MPa by small-angle neutron scattering

International audienceARTICLE scitation.org/journal/rsi A high pressure cell using metallic windows to investigate the structure of molecular solutions up to 600 MPa by small-angle neutron scattering Cite as: Rev. ABSTRACT We report on a high pressure (HP) cell designed for the determination of the structure of molecular solutions by small-angle neutron scattering (SANS). The HP cell is fitted up with two thick metallic windows that make the device very resistant under hydrostatic pressures up to 600 MPa (or 6 kbar). The metallic windows are removable, offering the possibility to adapt the HP cell to a given study with the pressure desired on an appropriate spatial range to study the structure of various molecular solutions by SANS. In this context, we report the absorption, transmission, and scattering properties of different metallic windows. Finally, we describe, as a proof of principle, the solution structure changes of myoglobin, a small globular protein. Published under license by AIP Publishing. https://doi

A high pressure cell using metallic windows to investigate the structure of molecular solutions up to 600 MPa by small-angle neutron scattering

International audienceARTICLE scitation.org/journal/rsi A high pressure cell using metallic windows to investigate the structure of molecular solutions up to 600 MPa by small-angle neutron scattering Cite as: Rev. ABSTRACT We report on a high pressure (HP) cell designed for the determination of the structure of molecular solutions by small-angle neutron scattering (SANS). The HP cell is fitted up with two thick metallic windows that make the device very resistant under hydrostatic pressures up to 600 MPa (or 6 kbar). The metallic windows are removable, offering the possibility to adapt the HP cell to a given study with the pressure desired on an appropriate spatial range to study the structure of various molecular solutions by SANS. In this context, we report the absorption, transmission, and scattering properties of different metallic windows. Finally, we describe, as a proof of principle, the solution structure changes of myoglobin, a small globular protein. Published under license by AIP Publishing. https://doi

The impact of high hydrostatic pressure on structure and dynamics of β-lactoglobulin

International audienceMethodsCombining small-angle X-ray and neutron scattering measurements with inelastic neutron scattering experiments, we investigated the impact of high hydrostatic pressure on the structure and dynamics of β-lactoglobulin (βLG) in aqueous solution.BackgroundβLG is a relatively small protein, which is predominantly dimeric in physiological conditions, but dissociates to monomer below about pH 3.ResultsHigh-pressure structural results show that the dimer–monomer equilibrium, as well as the protein–protein interactions, are only slightly perturbed by pressure, and βLG unfolding is observed above a threshold value of 3000 bar. In the same range of pressure, dynamical results put in evidence a slowing down of the protein dynamics in the picosecond timescale and a loss of rigidity of the βLG structure. This dynamical behavior can be related to the onset of unfolding processes, probably promoted from water penetration in the hydrophobic cavity.General significanceResults suggest that density and compressibility of water molecules in contact with the protein are key parameters to regulate the protein flexibility

SANS study of the self-organization of gradient copolymers with ligand groups in supercritical CO2

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Solubility and Self-Assembly of Amphiphilic Gradient and Block Copolymers in Supercritical CO2

International audienceThis work aims at demonstrating the interest of gradient copolymers in supercritical CO2 in comparison with block copolymers. Gradient copolymers exhibit a better solubility in supercritical CO2 than block copolymers, as attested by cloud point data. The self-assembly of gradient and block copolymers in dense CO2 has been characterized by Small-Angle Neutron Scattering (SANS) and it is shown that it is not fundamentally modified when changing from block copolymers to gradient copolymers. Therefore, gradient copolymers are advantageous thanks to their easier synthesis and their solubility at lower pressure while maintaining a good ability for self-organization in dense CO2