Our research activities:

FIBEr is performing research to push the current state-of-the-art of biomechanical testing. Our topics cover the complete workflow starting with experiment design and sample collection, over testing set-up, up to data processing and data storage. A few example of recent and ongoing studies are:

• Tissue preservation: from a logistics point of view, it is often easier to standardize time between tissue harvesting and preservation, than time between tissue harvesting and testing. Therefore, tissues are often preserved at low temperatures (-20 and -80 degrees Celsius) until testing, assuming that this process does not affect the mechanical properties. While some papers have studied the effect of preservation on their mechanical properties, literature is contradicting. Therefore, we have conducted our own study investigating the effect of different preservation methods on the mechanical properties of porcine aorta. Preliminary results can be found here. We conclude that every preservation method that we studied affected the stiffness, and the variability between tissues increased after preservation. Next steps include a follow up study in which the thawing process is altered between groups, and investigating how the tissues water retaining capabilities are affected by preservation.
• Testing standardization: testing standards or widely accepted protocols for the characterization of biological tissues is currently non-existent. While some guidelines are available for specific type of tests, testing protocols often vary widely in literature. Moreover, often reporting of testing protocols is incomplete, for example the value of certain experimental parameters are missing or the definition of extracted properties are lacking. As a result, also the results in literature vary widely since most of these parameters affects the final outcome of the test. This complicates a proper comparison between results of different research groups, but also makes it impossible to assess the reliability of results. Both the testing community and the regulating community want to solve this problem, and to this end, the C⁴Bio project was launched. C⁴Bio has a goal to develop consensus protocols for tissue characterization. FIBEr and FIBEr researchers are co-leading this initiative. Visit the C⁴Bio website for more information. Next to C⁴Bio, FIBEr is also working on smaller projects to investigate the influence of certain experimental or data processing parameters, and formulate guidelines for testing, data processing and reporting.
• Test optimization and innovation: we constantly try to improve our tests and data processing procedures. By assessing the repeatability and accuracy of our methods, we identify areas for improvement and work on those. This goes from mounting methods for our samples, to automating data processing to minimize the user dependency. In addition, we are also working on innovation of biomechanical testing.3 One example is the use of full field deformation measurements, which allows the development of new set-ups where multiple modes of deformation can be applied simultaneously. This field is also referred to as material testing 2.0, and allows to increase the information collected per test. This is especially interesting for the characterization of complex materials, such as biological tissues.