News

As part of a team of researchers from six countries we have contributed to the elucidation of hydration-induced structural changes in highly flexible brachiopod shells. Many thanks to Fabio Nudelman (University of Edinburgh) and Johannes Ihli (PSI) for the great collaboration and very enjoyable and fruitful beamtime at PSI!

The function-optimized properties of biominerals arise from the hierarchical organization of primary building blocks. Alteration of properties in response to environmental stresses generally involves time-intensive processes of resorption and reprecipitation of mineral in the underlying organic scaffold. Here, we report that the load-bearing shells of the brachiopod Discinisca tenuis are an exception to this process. These shells can dynamically modulate their mechanical properties in response to a change in environment, switching from hard and stiff when dry to malleable when hydrated within minutes. Using ptychographic X-ray tomography, electron microscopy and spectroscopy, we describe their hierarchical structure and composition as a function of hydration to understand the structural motifs that generate this adaptability. Key is a complementary set of structural modifications, starting with the swelling of an organic matrix on the micron level via nanocrystal reorganization and ending in an intercalation process on the molecular level in response to hydration.

Link to the original publication

Link to the press release of the Paul Scherrer Institute (PSI)