ESS seminar: Bone nanostructure

ESS Seminar: Bone Nanostructure - Insights from Scanning Small Angle X-ray Scattering

When: Wednesday 2010-03-17 14:00 - 15:00

Where: Lecture hall C, Chemistry department, Getingevägen 60, Lund, Sweden.

Speaker: Henrik Birkedal, Department of Chemistry & iNANO, Aarhus University, Denmark.

Abstract: Bone has a highly complex structure and is organized hierarchically from the atomic to the centimeter length scale – sort of like a molecular-scale Eiffel tower. It consists mainly of calcium phosphate nanocrystals and collagen type I fibers. The structure of bone determines its mechanical properties and hence its propensity for fracture. Bone structure is well understood down to around 10 micrometer; below this length scale many uncertainties remain. However, it is exactly at these length scales that bone quality is determined; i.e. the factors determining the risk of fracture.

We use small angle X-ray scattering (SAXS) to probe the structure of bone on the 1-100 nm length scale. By raster scanning the sample in the X-ray beam, maps of bone nanostructure can be obtained with a resolution corresponding to the X-ray beam diameter. Using SAXS on bone, one is sensitive to the bone nanocrystals. Two types of information can be obtained: the orientation of the crystallites and their thickness. Our methodologies for obtaining this information will be presented.

We will discuss examples of applications of SAXS on bone focusing on two distinct bone systems: the structural organization of growth plates, the loci of bone formation in growing juveniles, and on Sr-treatment of osteoporosis.