Biological materials science – bone as an adaptive material
At the Max Planck Institute in Potsdam we study biological materials from the perspective of materials science. With this research approach we follow two main aims: (i) to study structure-function relations in biological materials with respect to their medical and biological implications and (ii) to understand the „engineering design“ of natural materials to extract useful design principles for novel man-made materials (bio-inspired materials research). The presentation will introduce bone as a hierarchically structured material. The question will be asked of why biologically materials are hierarchically structured. Bone has the remarkable ability to adapt its structure to changes in the mechanical loading. Although this observation already dates back to Julius Wolff at the end of the 19th century, only recently important progress has been made to formulate “Wolff’s Law” in more quantitative terms. The key for this progress is the new possibility to perform multiple micro-tomography imaging in living animals. Still unclear is the role of the different bone cells in the sensation of mechanical stimuli. A key role is attributed to osteocytes, i.e. bone cells which are living in the mineralized bone matrix and which are connected with each other via their long cell processes. In a combination of staining methods and laser scanning confocal microscopy it is now possible to image this stupendous network-like porosity in which the osteocytes are living within our bones.