Studying Soft-matter and Biological Systems over a Wide Length-scale from Nanometer and Micrometer Sizes at the Small-angle Neutron Diffractometer KWS-2.

The KWS-2 SANS diffractometer is dedicated to the investigation of soft matter and biophysical systems covering a wide length scale, from nm to µm. The instrument is optimized for the exploration of the wide momentum transfer Q range between 1x10 and 0.5 Å by combining classical pinhole, focusing (with lenses), and time-of-flight (with chopper) methods, while simultaneously providing high-neutron intensities with an adjustable resolution.

Tuning the instrument resolution using chopper and time of flight at the small-angle neutron scattering diffractometer KWS-2.

Following demand from the user community regarding the possibility of improving the experimental resolution, the dedicated high-intensity/extended -range SANS diffractometer KWS-2 of the Jülich Centre for Neutron Science at the Heinz Maier-Leibnitz Center in Garching was equipped with a double-disc chopper with a variable opening slit window and time-of-flight (TOF) data acquisition option. The chopper used in concert with a dedicated high-intensity velocity selector enables the tuning at will of the wavelength resolution Δλ/λ within a broad range, from 20% (standard) down to 2%, in a convenient and safe manner following pre-planned or spontaneous decisions during the experiment. The new working mode is described in detail, and its efficiency is demonstrated on several standard samples with known properties and on a completely new crystallizable copolymer system, which were investigated using both the conventional (static) and TOF modes.

Fasted-state simulated intestinal fluid "FaSSIF-C", a cholesterol containing intestinal model medium for in vitro drug delivery development.

A set of biorelevant media "fasted-state simulated intestinal fluid with cholesterol (FaSSIF-C)" for the in vitro study of intestinal drug dissolution in the duodenum was developed. These contain cholesterol at the same levels as in human bile: the cholesterol content of FaSSIF-7C is equivalent to healthy female, FaSSIF-10C to healthy male persons, and FaSSIF-13C to several disease cases that lead to gallstones. The fluids were studied in three aspects: biocompatibility, intestinal nanostructure, and solubilizing power of hydrophobic drugs of the BCS class II.