The latest developments in XCT have led to systems with high spatial resolution (i.e. submicron voxel size) in which in-situ testing devices can be installed. This has opened possibilities for 3D investigation of the dynamic behavior of materials under loading (temperature, force, …). Indeed, a combination of XCT imaging with types of loading (so-called 4DXCT), such as mechanical forces, temperature changes, controlled atmosphere or surrounding liquid, brings unique opportunities to understand the functional behavior of materials. Additionally, evolution of the reconstruction algorithms and development of advance image processing tools such as Digital Volume Correlation (DVC) has allowed further improvements in terms of scanning speed and quantitative analysis of the datasets, respectively. For biological tissues, the contrast in XCT images is inherently poor and additional contrast-enhancing staining agents (CESAs) are required to achieve proper 3D structural information. Within our research group, we are developing novel non-destructive CESAs for different soft biological tissues. The aim of this project is to couple 4D-XCT with CE-CT to monitor in 3D microstructural changes of soft biological tissues (i.e. 4D CECT), as well as complex hybrids and architectured materials, during dynamic mechanical testing. This will lead to a more intelligent and robust design of novel repair solutions (for biological tissues) and materials and their production processes. In first instance, we will assess the influence of the CESA (type, staining time, concentration) on the mechanical properties of the tissues, and we will select the CESA that is the least harmful. Additionally, new in-situ stages will be developed specifically for mechanical assessment of biological tissues. Finally, DVC techniques will be tested and optimized.