Investigating Structure and Dynamics of Proteins in Amorphous Phases Using Neutron Scattering

Abstract

In order to increase shelf life and minimize aggregation during storage, many biotherapeutic drugs are formulated and stored as either frozen solutions or lyophilized powders. However, characterizing amorphous solids can be challenging with the commonly available set of biophysical measurements used for proteins in liquid solutions. Therefore, some questions remain regarding the structure of the active pharmaceutical ingredient during freezing and drying of the drug product and the molecular role of excipients. Neutron scattering is a powerful technique to study structure and dynamics of a variety of systems in both solid and liquid phases. Moreover, neutron scattering experiments can generally be correlated with theory and molecular simulations to analyze experimental data. In this article, we focus on the use of neutron techniques to address problems of biotechnological interest. We describe the use of small-angle neutron scattering to study the solution structure of biological molecules and the packing arrangement in amorphous phases, that is, frozen glasses and freeze-dried protein powders. In addition, we discuss the use of neutron spectroscopy to measure the dynamics of glassy systems at different time and length scales. Overall, we expect that the present article will guide and prompt the use of neutron scattering to provide unique insights on many of the outstanding questions in biotechnology.

Hybrid boron-10 gaseous detector for slow and fast neutron simultaneous detection

“…The 10 B detector was located at a 4 m distance from the source centre. The 3 He detector served as a flux monitor. The coordinate distribution on X-axis and Y-axis is shown in Fig.2.…”

“…There are many applications of neutron positionsensitive detectors in physics [1], technology [2] and biology [3]. The choice of a kind of detector depends on the energy range of neutrons.…”

“…Usually, 3 He-and 10 BF 3 -tube counters and their assemblies are widely used in a diffraction setup and in small angle scattering. The position sensitive proportional chamber filled by 3 He under high pressure [8] or 10 BF 3 is more rare and expensive device. A proportional chamber and a assembly of tube counters filled by the 3 He gas have a high efficiency and low sensitivity to γ-rays.…”

“…The position sensitive proportional chamber filled by 3 He under high pressure [8] or 10 BF 3 is more rare and expensive device. A proportional chamber and a assembly of tube counters filled by the 3 He gas have a high efficiency and low sensitivity to γ-rays. But they operate under a high pressure and have a thick entrance window and may experience leakage of expensive gas.…”

Designing a bioremediator: mechanistic models guide cellular and molecular specialization

“…SANS uses low-energy thermal neutrons with wavelength and energy ranges which can resolve information on the nanometer to micrometer length scales, making it a wellsuited technique for the study of the mesoscopic structure of proteins, enzymes, and complex macromolecules in a variety of phases. In a SANS experiment, information about the spatial arrangement of the secondary structure of the assembly is encoded in two factors: the particle form factor P(Q) and the structure factor S(Q), Q being the neutron momentum transfer [33]. These functions can be calculated using analytical models and numerical tools, such as ab initio or Monte Carlo methods.…”