Röntgen-Ångström-Cluster (RAC) "JOINT"

The smooth motion of our joints is based on the complex interplay between cartilage, which is a highly specialized nanostructured tissue, and the lubricating ability of self-assembly structures formed by the molecules of the synovial fluid. It results in friction coefficients which are the lowest found in nature (0.001 – 0.01) and which are difficult to reach in technical processes. The molecular components of the synovial fluid are largely known, and include water, hyaluronic acid, lipids, proteins and glycoproteins. They self-assemble and form a thin lubrication film on the cartilage.

However, there is no clear picture of how the molecules interact and how they and the structures they form generate the nearly frictionless movement of joints under load and rapidly changing shear conditions.

JOINT is a project realised by German and Swedish partners in order to build sample environments for two types of measurements. The first intends to exploit the specific nano beam geometry available at the nano focus set up of the MINAXS beamline (Micro and nano focus X-ray Scattering) at PETRA III to perform SAXS and GISAXS measurements under load and shear. This should provide structural information on the molecular organisation with high spatial and temporal resolution. In a second set up the aim is to explore the molecular organisation under load and shear on cartilage or implant materials.

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