Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Why do bones fail?

27.08.2019

Can analytical methods from materials science help us better understand human bones? A research team at Empa in Thun is pursuing precisely this approach.

Osteoporosis is a wide­spread disease. Every third woman and every fifth man are affected by bone loss with ad­vanc­ing age. A frequent consequence of this is a fracture of the femoral neck – a painful injury that massively impairs the quality of life of those affected. Pa­tients must reckon with longterm loss of mobility. Long bed rest and the associated often poor general condition even lead to an increased mortality rate.


The disease causes a loss of bone mass due to an imbalance in the natural remodelling process in the tissue and changes in bone quality. These changes affect the microstructure, density of microcracks and tissue properties.

Bones have an extremely complex structure. If, for example, a thigh bone is sawed open, it can be seen that it consists of a hard outer layer and a porous filling. Under the microscope, cylindrical structures of concentric lamellae are visible inside the hard shell, arranged around central blood vessels.

These individual lamellae are only a few thou­sandths of a millimetre thick and consist of a type of natural fibre composite material: collagen fibres in which mineral particles are embedded, embedded in a protein-containing mineral matrix. The higher the mineralization, the stiffer and more fragile the bone.

This hierarchical structure allows the bones to be robust and resistant despite their relatively low density. When bones fracture, it is therefore not sufficient to consider only the density and structure of the bone at the macro level – mechanisms in all scale ranges are responsible for the fracture.

Material analysis for bone

A research group at Empa in Thun led by Jakob Schwiedrzik aims to gain a better understanding of bone failure at the lamella level. "If one only considers bone density, as is usually the case in clinical practice today, the risk of fracture for patients can be predicted relatively well on average.

In individual cases, however, the results may differ considerably and the effective fracture risk may be incorrectly assessed," explains Schwiedrzik. "We hope that our research will enable us to make more accurate predictions for each individual patient in the future".

The researchers are using methods that are actually at home in materials research: They subject even the smallest samples of bone material containing only a single lamella to tensile and com-pression tests.

They are investigating how the material fails and how the measured properties are related to the underlying microstructure. In microstructure analysis, Raman spectroscopy and transmission electron microscopes are used – highly complex instruments that make it possible to precisely observe structural changes in the test objects.

"At the moment, the production and testing of a single bone sample still requires a great deal of time – especially for tensile tests," explains Schwiedrzik. To do this, samples with a defined geometry must first be produced from the material used using a focused ion beam. In order to be able to analyze more samples in less time in the future and to enable statistical evaluation of the experiments, a large part of the current work consists of automating the sample heart position and developing our own measurement setups.

Personal diagnosis

The question of how the methods developed can be used for clinical studies is exciting. A project is currently underway involving researchers from the Inselspital Bern, the University of Bern, ETH Zurich and Empa. Bone material from patients who have received a hip implant is being investigated.

This material will be analysed on several length scales. The aim is to collect data on micromechanical properties, microstructure, cell activity and metabolism and to correlate these with clinical findings and patient data using machine learning. The resulting database will make it possible to quantify the bone quality of a patient and include it in the diagnosis.

Wissenschaftliche Ansprechpartner:

Dr. Jakob Schwiedrzik
Mechanics of Materials and Nanostructures
Phone +41 58 765 63 52
jakob.schwiedrzik@empa.ch

Editor / Media contact
Karin Weinmann
Communications
Phone +41 58 765 47 08
redaktion@empa.ch

Originalpublikation:

https://www.sciencedirect.com/science/article/abs/pii/S8756328215004196

Weitere Informationen:

https://www.empa.ch/web/s206/biomechanics-research

Rainer Klose | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

More articles from Materials Sciences:

nachricht A robot and software make it easier to create advanced materials
06.12.2019 | Rutgers University

nachricht First field measurements of laughing gas isotopes
05.12.2019 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Developing a digital twin

University of Texas and MIT researchers create virtual UAVs that can predict vehicle health, enable autonomous decision-making

In the not too distant future, we can expect to see our skies filled with unmanned aerial vehicles (UAVs) delivering packages, maybe even people, from location...

Im Focus: The coldest reaction

With ultracold chemistry, researchers get a first look at exactly what happens during a chemical reaction

The coldest chemical reaction in the known universe took place in what appears to be a chaotic mess of lasers. The appearance deceives: Deep within that...

Im Focus: How do scars form? Fascia function as a repository of mobile scar tissue

Abnormal scarring is a serious threat resulting in non-healing chronic wounds or fibrosis. Scars form when fibroblasts, a type of cell of connective tissue, reach wounded skin and deposit plugs of extracellular matrix. Until today, the question about the exact anatomical origin of these fibroblasts has not been answered. In order to find potential ways of influencing the scarring process, the team of Dr. Yuval Rinkevich, Group Leader for Regenerative Biology at the Institute of Lung Biology and Disease at Helmholtz Zentrum München, aimed to finally find an answer. As it was already known that all scars derive from a fibroblast lineage expressing the Engrailed-1 gene - a lineage not only present in skin, but also in fascia - the researchers intentionally tried to understand whether or not fascia might be the origin of fibroblasts.

Fibroblasts kit - ready to heal wounds

Im Focus: McMaster researcher warns plastic pollution in Great Lakes growing concern to ecosystem

Research from a leading international expert on the health of the Great Lakes suggests that the growing intensity and scale of pollution from plastics poses serious risks to human health and will continue to have profound consequences on the ecosystem.

In an article published this month in the Journal of Waste Resources and Recycling, Gail Krantzberg, a professor in the Booth School of Engineering Practice...

Im Focus: Machine learning microscope adapts lighting to improve diagnosis

Prototype microscope teaches itself the best illumination settings for diagnosing malaria

Engineers at Duke University have developed a microscope that adapts its lighting angles, colors and patterns while teaching itself the optimal...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

The Future of Work

03.12.2019 | Event News

First International Conference on Agrophotovoltaics in August 2020

15.11.2019 | Event News

Laser Symposium on Electromobility in Aachen: trends for the mobility revolution

15.11.2019 | Event News

 
Latest News

Solving the mystery of carbon on ocean floor

06.12.2019 | Earth Sciences

Chip-based optical sensor detects cancer biomarker in urine

06.12.2019 | Life Sciences

A platform for stable quantum computing, a playground for exotic physics

06.12.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>