Scientists at the Paul Scherrer Institute PSI have refined an X-ray diffraction technique for detecting biological structures from nanometres to millimetres – reducing the time needed to make the measurement from around one day to about an hour. This opens up a wide range of possibilities for biomedical research – from analysing bone and tissue structures to supporting the development of new implants.
Biological materials are masterpieces created by nature. Bones, for example, are extremely hard, yet at the same time elastic enough to withstand lateral forces without breaking easily. This combination of properties results from their hierarchical structure as composite materials – they combine materials that have different structures on different scales. Human-made composite materials are similar in the way they are made up. In reinforced concrete, for example, the concrete component, consisting of cement and sand, can withstand high pressure, while a steel mesh provides high tensile strength and transverse stability.
Until now, examining such biological materials in detail has required the use of several different instruments, such as electron microscopes or classic light microscopes. However, scientists at the PSI Center for Photon Science have now refined an X-ray diffraction technique that was developed at the institute ten years ago, allowing it to be used to characterise materials on scales from nanometres to millimetres simultaneously and much faster than before. A complete scan now only takes about an hour, instead of a whole day.
To demonstrate the efficiency of their method, the researchers used the Swiss Light Source SLS to reveal the alignment of collagen fibres in a human ossicle known as the incus, or anvil. Collagen fibres are thread-like protein structures that provide tensile strength and elasticity to bones. “In doing so, we have taken the leap from a scientific method to a practical technique,” says Christian Appel, postdoctoral researcher and first author of the study. The results have now been published in the journal Small Methods as its cover story. In future, this method could be valuable in areas such as the study of complex tissue, the analysis of bone diseases and the optimisation of implant designs.
Read more on the PSI website
Image: Scientists at PSI were able to observe the local collagen structures in an ossicle by scanning it with an X-ray beam. The different colours of the cylinders indicate how strongly the collagen bundles are spatially aligned in a section measuring 20 by 20 by 20 micrometres.
Credit: © Paul Scherrer Institute PSI/Christian Appel