Lara Mazy
PhD student
Ir. at UCLouvain in 2021

Main project: Design and optimization of a novel tool to dynamically assess in 3D how the microstructure of biological tissues changes during mechanical loading
Funding: FRIA
Supervisor(s): Greet Kerckhofs

Most biological tissues undergo physiological mechanical loading during their functioning in vivo. To be able to properly respond to these mechanical signals, tissues have a highly complex microstructural organization. However, to date there is not yet sufficient knowledge about the link between the microstructural organization of tissues and their mechanical behaviour.
Therefore, this PhD project aims to design and optimize a novel tool that allows to dynamically assess in 3D how the microstructure of biological tissues changes during mechanical loading, namely 4D contrast-enhanced microfocus computed tomography (µCT) or 4D-CECT. It combines high-resolution 3D µCT imaging of unmineralized biological tissues using X-ray contrast-enhancing staining agents with in-situ mechanical loading. As only limited research has been done using this technique, the goal of this project is to improve the overall performance of 4D-CECT.
More specifically, this project aims to provide an answer to the following research questions:
How does the image acquisition (application of X-rays, heating up and potential dehydration of the tissues) affect the mechanical properties of the biological tissues, and how can these effects be minimized?

Can we design an in-situ loading stage with more complex loading regimes than uniaxial tensile or compression?

Which level of image quality is required to accurately detect changes in the microstructure and quantify the local strains occurring in the entire tissue during loading, using dedicated image postprocessing on the 4D-CECT data?

Can this novel technique be applied to study the effect of disease on the mechanical behaviour of both hard and soft unmineralized tissues, such as cartilage and vascular tissue?

To do this, the first objective is to improve the current in-situ tensile/compression loading stages by incorporating temperature and humidity control. We will also extend the stages to more complex loading modes, such as biaxial testing, since biological tissues are most often in vivo not just imposed to simple uniaxial forces. The second objective is to optimize the image acquisition and reconstruction, and this to avoid tissue damage as well as to obtain sufficient image quality to be able to determine the microstructural changes during loading and to obtain accurate quantitative data on the local strain distribution. To achieve these objectives, healthy vascular tissues and cartilage will be used; two unmineralized tissues, but strongly different in their structure and function. Finally, our novel and optimized technique will be applied to try to better understand how diseases alter the mechanical behaviour of tissues.

IMMC main research direction(s):
Biomedical engineering
Processing and characterisation of materials

contrast-enhanced computed tomography

Research group(s): MEED